WorldWideScience

Sample records for sphingosine-1-phosphate receptor type

  1. Agonist-dependent effects of mutations in the sphingosine-1-phosphate type 1 receptor

    van Loenen, Pieter B.; de Graaf, Chris; Verzijl, Dennis; Leurs, Rob; Rognan, Didier; Peters, Stephan L. M.; Alewijnse, Astrid E.

    2011-01-01

    The sphingosine-1-phosphate type 1 (S1P(1)) receptor is a new target in the treatment of auto-immune diseases as evidenced by the recent approval of FTY720 (Fingolimod). The ligand-binding pocket of the S1P(1) receptor has been generally characterised but detailed insight into ligand-specific

  2. High density lipoprotein stimulated migration of macrophages depends on the scavenger receptor class B, type I, PDZK1 and Akt1 and is blocked by sphingosine 1 phosphate receptor antagonists.

    Aishah Al-Jarallah

    Full Text Available HDL carries biologically active lipids such as sphingosine-1-phosphate (S1P and stimulates a variety of cell signaling pathways in diverse cell types, which may contribute to its ability to protect against atherosclerosis. HDL and sphingosine-1-phosphate receptor agonists, FTY720 and SEW2871 triggered macrophage migration. HDL-, but not FTY720-stimulated migration was inhibited by an antibody against the HDL receptor, SR-BI, and an inhibitor of SR-BI mediated lipid transfer. HDL and FTY720-stimulated migration was also inhibited in macrophages lacking either SR-BI or PDZK1, an adaptor protein that binds to SR-BI's C-terminal cytoplasmic tail. Migration in response to HDL and S1P receptor agonists was inhibited by treatment of macrophages with sphingosine-1-phosphate receptor type 1 (S1PR1 antagonists and by pertussis toxin. S1PR1 activates signaling pathways including PI3K-Akt, PKC, p38 MAPK, ERK1/2 and Rho kinases. Using selective inhibitors or macrophages from gene targeted mice, we demonstrated the involvement of each of these pathways in HDL-dependent macrophage migration. These data suggest that HDL stimulates the migration of macrophages in a manner that requires the activities of the HDL receptor SR-BI as well as S1PR1 activity.

  3. Signal Transduction of Sphingosine-1-Phosphate G Protein—Coupled Receptors

    Nicholas Young

    2006-01-01

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive lipid capable of eliciting dramatic effects in a variety of cell types. Signaling by this molecule is by a family of five G protein—coupled receptors named S1P1–5 that signal through a variety of pathways to regulate cell proliferation, migration, cytoskeletal organization, and differentiation. These receptors are expressed in a wide variety of tissues and cell types, and their cellular effects contribute to important biological and pathological functions of S1P in many processes, including angiogenesis, vascular development, lymphocyte trafficking, and cancer. This review will focus on the current progress in the field of S1P receptor signaling and biology.

  4. The sphingosine 1-phosphate receptor S1P(2) triggers hepatic wound healing

    Serriere-Lanneau, Valerie; Teixeira-Clerc, Fatima; Li, Liying; Schippers, Marlies; de Wries, Willie; Julien, Boris; Tran-Van-Nhieu, Jeanne; Manin, Sylvie; Poelstra, Klaas; Chun, Jerold; Carpentier, Stephane; Levade, Thierry; Mallat, Ariane; Lotersztajn, Sophie

    Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid produced by sphingosine kinase (SphK1 and 2). We previously showed that S1P receptors (S1P(1), S1P(2), and S1P(3)) are expressed in hepatic myofibroblasts (hMF), a population of cells that triggers matrix remodeling during liver injury. Here

  5. Sphingosine-1-Phosphate and Its Receptors: A Mutual Link between Blood Coagulation and Inflammation

    Shailaja Mahajan-Thakur

    2015-01-01

    Full Text Available Sphingosine-1-phosphate (S1P is a versatile lipid signaling molecule and key regulator in vascular inflammation. S1P is secreted by platelets, monocytes, and vascular endothelial and smooth muscle cells. It binds specifically to a family of G-protein-coupled receptors, S1P receptors 1 to 5, resulting in downstream signaling and numerous cellular effects. S1P modulates cell proliferation and migration, and mediates proinflammatory responses and apoptosis. In the vascular barrier, S1P regulates permeability and endothelial reactions and recruitment of monocytes and may modulate atherosclerosis. Only recently has S1P emerged as a critical mediator which directly links the coagulation factor system to vascular inflammation. The multifunctional proteases thrombin and FXa regulate local S1P availability and interact with S1P signaling at multiple levels in various vascular cell types. Differential expression patterns and intracellular signaling pathways of each receptor enable S1P to exert its widespread functions. Although a vast amount of information is available about the functions of S1P and its receptors in the regulation of physiological and pathophysiological conditions, S1P-mediated mechanisms in the vasculature remain to be elucidated. This review summarizes recent findings regarding the role of S1P and its receptors in vascular wall and blood cells, which link the coagulation system to inflammatory responses in the vasculature.

  6. Prolonging survival of corneal transplantation by selective sphingosine-1-phosphate receptor 1 agonist.

    Min Gao

    Full Text Available Corneal transplantation is the most used therapy for eye disorders. Although the cornea is somewhat an immune privileged organ, immune rejection is still the major problem that reduces the success rate. Therefore, effective chemical drugs that regulate immunoreactions are needed to improve the outcome of corneal transplantations. Here, a sphingosine-1-phosphate receptor 1 (S1P1 selective agonist was systematically evaluated in mouse allogeneic corneal transplantation and compared with the commonly used immunosuppressive agents. Compared with CsA and the non-selective sphingosine 1-phosphate (S1P receptor agonist FTY720, the S1P1 selective agonist can prolong the survival corneal transplantation for more than 30 days with a low immune response. More importantly, the optimal dose of the S1P1 selective agonist was much less than non-selective S1P receptor agonist FTY720, which would reduce the dose-dependent toxicity in drug application. Then we analyzed the mechanisms of the selected S1P1 selective agonist on the immunosuppression. The results shown that the S1P1 selective agonist could regulate the distribution of the immune cells with less CD4+ T cells and enhanced Treg cells in the allograft, moreover the expression of anti-inflammatory cytokines TGF-β1 and IL-10 unregulated which can reduce the immunoreactions. These findings suggest that S1P1 selective agonist may be a more appropriate immunosuppressive compound to effectively prolong mouse allogeneic corneal grafts survival.

  7. Role of sphingosine 1-phosphate receptor expression in eosinophils of patients with allergic rhinitis, and effect of topical nasal steroid treatment on this receptor expression.

    Mackle, T

    2008-12-01

    Recent research has indicated that sphingosine 1-phosphate plays a role in allergy. This study examined the effect of allergen challenge on the expression of sphingosine 1-phosphate receptors on the eosinophils of allergic rhinitis patients, and the effect of steroid treatment on this expression.

  8. Different response patterns of several ligands at the sphingosine-1-phosphate receptor subtype 3 (S1P(3))

    Jongsma, M.; van Unen, J.; van Loenen, P. B.; Michel, M. C.; Peters, S. L. M.; Alewijnse, A. E.

    2009-01-01

    Recently, some ligands targeting the sphingosine-1-phosphate receptor subtype 3 (S1P(3)) have become available. The characterization of these compounds was mainly based on one functional read-out system, although S1P(3) receptors are known to activate different signal transduction pathways.

  9. A sphingosine 1-phosphate receptor agonist ameliorates animal model of vasculitis.

    Miyabe, Chie; Miyabe, Yoshishige; Komiya, Takaki; Shioya, Hiroki; Miura, Noriko N; Takahashi, Kei; Ohno, Naohito; Tsuboi, Ryoji; Luster, Andrew D; Kawai, Shinichi; Miyasaka, Nobuyuki; Nanki, Toshihiro

    2017-04-01

    Sphingosine 1-phosphate (S1P) is a bioactive lipid that binds to cell surface receptors (S1P 1-5 ). In this study, we examined the effect of S1P 1 agonist, ONO-W061, on murine Candida albicans water-soluble fraction (CAWS)-induced vasculitis. Mice were administered ONO-W061, and the number of peripheral blood cells was counted. Vasculitis was induced by an intraperitoneal injection of CAWS. Expression of S1P receptors and CXCL1 was analyzed by quantitative RT-PCR. ONO-W061 was orally administered, and vasculitis was evaluated histologically. Number of neutrophils, macrophages and T cells in the vasculitis tissue was counted using flow cytometry. Production of chemokines from S1P-stimulated human umbilical vein endothelial cells (HUVECs) was measured by ELISA. Number of peripheral blood lymphocytes was decreased by ONO-W061. Expression of CXCL1 and S1P 1 was enhanced in CAWS-induced vasculitis tissue. Vasculitis score, CXCL1 and number of neutrophils in the vasculitis tissue were lower in ONO-W061-treated mice. Treatment of HUVECs with S1P upregulated the production of CXCL1 and IL-8 in vitro, and this was inhibited by ONO-W061. ONO-W061 significantly improved CAWS-induced vasculitis. This effect may be partly exerted through the inhibited production of chemokines by endothelial cells, which in turn could induce neutrophil recruitment into inflamed vessels.

  10. Hematopoietic sphingosine 1-phosphate lyase deficiency decreases atherosclerotic lesion development in LDL-receptor deficient mice.

    Martine Bot

    Full Text Available AIMS: Altered sphingosine 1-phosphate (S1P homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1(-/- deficiency on leukocyte subsets relevant to atherosclerosis. METHODS AND RESULTS: LDL receptor deficient mice that were transplanted with Sgpl1(-/- bone marrow showed disrupted S1P gradients translating into lymphopenia and abrogated lymphocyte mitogenic and cytokine response as compared to controls. Remarkably however, Sgpl1(-/- chimeras displayed mild monocytosis, due to impeded stromal retention and myelopoiesis, and plasma cytokine and macrophage expression patterns, that were largely compatible with classical macrophage activation. Collectively these two phenotypic features of Sgpl1 deficiency culminated in diminished atherogenic response. CONCLUSIONS: Here we not only firmly establish the critical role of hematopoietic S1P lyase in controlling S1P levels and T cell trafficking in blood and lymphoid tissue, but also identify leukocyte Sgpl1 as critical factor in monocyte macrophage differentiation and function. Its, partly counterbalancing, pro- and anti-inflammatory activity spectrum imply that intervention in S1P lyase function in inflammatory disorders such as atherosclerosis should be considered with caution.

  11. Sphingosine 1-Phosphate Receptor 1 as a Useful Target for Treatment of Multiple Sclerosis

    Kunitomo Adachi

    2012-05-01

    Full Text Available Sphingosine 1-phosphate (S1P, a lysophospholipid mediator, is generated from sphingosine by sphingosine kinases and binds five known cell surface receptors. S1P receptor 1 (S1P1 plays an essential role in lymphocyte egress from secondary lymphoid organs (SLO, as evinced by the inability of lymphocytes to exit from the SLO in mice lacking lymphocytic S1P1. Fingolimod hydrochloride (FTY720 is a first-in-class, orally active, S1P receptor modulator with a structure closely related to sphingosine. FTY720 was first synthesized by chemical modification of a natural product, myriocin. FTY720 is effectively converted to an active metabolite, FTY720 phosphate (FTY720-P by sphingosine kinases. FTY720-P shows high affinity to 4 of the S1P receptors (S1P1, S1P3, S1P4, and S1P5. In particular, FTY720-P strongly induces internalization and degradation of S1P1, inhibits S1P responsiveness of lymphocytes in the SLO, and acts as a functional antagonist at lymphocytic S1P1. Consequently, FTY720 inhibits S1P1-dependent lymphocyte egress from the SLO to decrease circulation of lymphocytes including autoreactive Th17 cells and is highly effective in experimental autoimmune encephalomyelitis (EAE, an animal model of multiple sclerosis (MS. Because FTY720 shows a superior efficacy in relapsing remitting MS patients compared to intramuscular interferon-β-1a (Avonex®, S1P1 is presumed to be a useful target for the therapy of MS.

  12. Hematopoietic Sphingosine 1-Phosphate Lyase Deficiency Decreases Atherosclerotic Lesion Development in LDL-Receptor Deficient Mice

    Bot, Martine; Van Veldhoven, Paul P.; de Jager, Saskia C. A.; Johnson, Jason; Nijstad, Niels; Van Santbrink, Peter J.; Westra, Marijke M.; Van Der Hoeven, Gerd; Gijbels, Marion J.; Mueller-Tidow, Carsten; Varga, Georg; Tietge, Uwe J. F.; Kuiper, Johan; Van Berkel, Theo J. C.; Nofer, Jerzy-Roch; Bot, Ilze; Biessen, Erik A. L.

    2013-01-01

    Aims: Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1(-/-)) deficiency on leukocyte subsets

  13. Hematopoietic Sphingosine 1-Phosphate Lyase Deficiency Decreases Atherosclerotic Lesion Development in LDL-Receptor Deficient Mice

    Bot, M.; Veldhoven, van P.P.; Jager, de S.C.; Johnson, J.; Nijstad, N.; van, Santbrink P.J.; Westra, M.M.; Hoeven, van der G.; Gijbels, M.J.; Muller-Tidow, C.; Varga, G.; Tietge, U.J.; Kuiper, J.; Berkel, van T.J.; Nofer, J.R.; Bot, I.; Biessen, E.A.

    2013-01-01

    Abstract Aims Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1−/−) deficiency on leukocyte

  14. Hematopoietic sphingosine 1-phosphate lyase deficiency decreases atherosclerotic lesion development in LDL-receptor deficient mice

    Bot, Martine; van Veldhoven, Paul P.; de Jager, Saskia C. A.; Johnson, Jason; Nijstad, Niels; van Santbrink, Peter J.; Westra, Marijke M.; van der Hoeven, Gerd; Gijbels, Marion J.; Müller-Tidow, Carsten; Varga, Georg; Tietge, Uwe J. F.; Kuiper, Johan; van Berkel, Theo J. C.; Nofer, Jerzy-Roch; Bot, Ilze; Biessen, Erik A. L.

    2013-01-01

    Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1(-/-)) deficiency on leukocyte subsets relevant to

  15. Sphingosine Kinases and Sphingosine 1-Phosphate Receptors: Signaling and Actions in the Cardiovascular System

    Alessandro Cannavo

    2017-08-01

    Full Text Available The sphingosine kinases 1 and 2 (SphK1 and 2 catalyze the phosphorylation of the lipid, sphingosine, generating the signal transmitter, sphingosine 1-phosphate (S1P. The activation of such kinases and the subsequent S1P generation and secretion in the blood serum of mammals represent a major checkpoint in many cellular signaling cascades. In fact, activating the SphK/S1P system is critical for cell motility and proliferation, cytoskeletal organization, cell growth, survival, and response to stress. In the cardiovascular system, the physiological effects of S1P intervene through the binding and activation of a family of five highly selective G protein-coupled receptors, called S1PR1-5. Importantly, SphK/S1P signal is present on both vascular and myocardial cells. S1P is a well-recognized survival factor in many tissues. Therefore, it is not surprising that the last two decades have seen a flourishing of interest and investigative efforts directed to obtain additional mechanistic insights into the signaling, as well as the biological activity of this phospholipid, and of its receptors, especially in the cardiovascular system. Here, we will provide an up-to-date account on the structure and function of sphingosine kinases, discussing the generation, release, and function of S1P. Keeping the bull’s eye on the cardiovascular system, we will review the structure and signaling cascades and biological actions emanating from the stimulation of different S1P receptors. We will end this article with a summary of the most recent, experimental and clinical observations targeting S1PRs and SphKs as possible new therapeutic avenues for cardiovascular disorders, such as heart failure.

  16. Critical role of sphingosine-1-phosphate receptor 2 (S1PR2) in acute vascular inflammation.

    Zhang, Guoqi; Yang, Li; Kim, Gab Seok; Ryan, Kieran; Lu, Shulin; O'Donnell, Rebekah K; Spokes, Katherine; Shapiro, Nathan; Aird, William C; Kluk, Michael J; Yano, Kiichiro; Sanchez, Teresa

    2013-07-18

    The endothelium, as the interface between blood and all tissues, plays a critical role in inflammation. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid, highly abundant in plasma, that potently regulates endothelial responses through interaction with its receptors (S1PRs). Here, we studied the role of S1PR2 in the regulation of the proadhesion and proinflammatory phenotype of the endothelium. By using genetic approaches and a S1PR2-specific antagonist (JTE013), we found that S1PR2 plays a key role in the permeability and inflammatory responses of the vascular endothelium during endotoxemia. Experiments with bone marrow chimeras (S1pr2(+/+) → S1pr2(+/+), S1pr2(+/+) → S1pr2(-/-), and S1pr2(-/-) → S1pr2(+/+)) indicate the critical role of S1PR2 in the stromal compartment, in the regulation of vascular permeability and vascular inflammation. In vitro, JTE013 potently inhibited tumor necrosis factor α-induced endothelial inflammation. Finally, we provide detailed mechanisms on the downstream signaling of S1PR2 in vascular inflammation that include the activation of the stress-activated protein kinase pathway that, together with the Rho-kinase nuclear factor kappa B pathway (NF-kB), are required for S1PR2-mediated endothelial inflammatory responses. Taken together, our data indicate that S1PR2 is a key regulator of the proinflammatory phenotype of the endothelium and identify S1PR2 as a novel therapeutic target for vascular disorders.

  17. Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation

    Sato, Chieri [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Iwasaki, Tsuyoshi, E-mail: tsuyo-i@huhs.ac.jp [Division of Pharmacotherapy, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, 1-3-6 Minatojima, Chuo-ku, Kobe 650-8530 (Japan); Kitano, Sachie; Tsunemi, Sachi; Sano, Hajime [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan)

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer We investigated the role of S1P signaling for osteoblast differentiation. Black-Right-Pointing-Pointer Both S1P and FTY enhanced BMP-2-stimulated osteoblast differentiation by C2C12 cells. Black-Right-Pointing-Pointer S1P signaling enhanced BMP-2-stimulated Smad and ERK phosphorylation by C2C12 cells. Black-Right-Pointing-Pointer MEK/ERK signaling is a pathway underlying S1P signaling for osteoblast differentiation. -- Abstract: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P

  18. Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation

    Sato, Chieri; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sano, Hajime

    2012-01-01

    Highlights: ► We investigated the role of S1P signaling for osteoblast differentiation. ► Both S1P and FTY enhanced BMP-2-stimulated osteoblast differentiation by C2C12 cells. ► S1P signaling enhanced BMP-2-stimulated Smad and ERK phosphorylation by C2C12 cells. ► MEK/ERK signaling is a pathway underlying S1P signaling for osteoblast differentiation. -- Abstract: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P receptor-mediated signaling plays a crucial role for osteoblast differentiation.

  19. Sphingosine 1-phosphate receptor 5 mediates the immune quiescence of the human brain endothelial barrier

    van Doorn Ruben

    2012-06-01

    Full Text Available Abstract Background The sphingosine 1-phosphate (S1P receptor modulator FTY720P (Gilenya® potently reduces relapse rate and lesion activity in the neuroinflammatory disorder multiple sclerosis. Although most of its efficacy has been shown to be related to immunosuppression through the induction of lymphopenia, it has been suggested that a number of its beneficial effects are related to altered endothelial and blood–brain barrier (BBB functionality. However, to date it remains unknown whether brain endothelial S1P receptors are involved in the maintenance of the function of the BBB thereby mediating immune quiescence of the brain. Here we demonstrate that the brain endothelial receptor S1P5 largely contributes to the maintenance of brain endothelial barrier function. Methods We analyzed the expression of S1P5 in human post-mortem tissues using immunohistochemistry. The function of S1P5 at the BBB was assessed in cultured human brain endothelial cells (ECs using agonists and lentivirus-mediated knockdown of S1P5. Subsequent analyses of different aspects of the brain EC barrier included the formation of a tight barrier, the expression of BBB proteins and markers of inflammation and monocyte transmigration. Results We show that activation of S1P5 on cultured human brain ECs by a selective agonist elicits enhanced barrier integrity and reduced transendothelial migration of monocytes in vitro. These results were corroborated by genetically silencing S1P5 in brain ECs. Interestingly, functional studies with these cells revealed that S1P5 strongly contributes to brain EC barrier function and underlies the expression of specific BBB endothelial characteristics such as tight junctions and permeability. In addition, S1P5 maintains the immunoquiescent state of brain ECs with low expression levels of leukocyte adhesion molecules and inflammatory chemokines and cytokines through lowering the activation of the transcription factor NFκB. Conclusion Our

  20. Sphingosine-1-Phosphate Receptor-1 Selective Agonist Enhances Collateral Growth and Protects against Subsequent Stroke.

    Masahiko Ichijo

    Full Text Available Collateral growth after acute occlusion of an intracranial artery is triggered by increasing shear stress in preexisting collateral pathways. Recently, sphingosine-1-phosphate receptor-1 (S1PR1 on endothelial cells was reported to be essential in sensing fluid shear stress. Here, we evaluated the expression of S1PR1 in the hypoperfused mouse brain and investigated the effect of a selective S1PR1 agonist on leptomeningeal collateral growth and subsequent ischemic damage after focal ischemia.In C57Bl/6 mice (n = 133 subjected to unilateral common carotid occlusion (CCAO and sham surgery. The first series examined the time course of collateral growth, cell proliferation, and S1PR1 expression in the leptomeningeal arteries after CCAO. The second series examined the relationship between pharmacological regulation of S1PR1 and collateral growth of leptomeningeal anastomoses. Animals were randomly assigned to one of the following groups: LtCCAO and daily intraperitoneal (i.p. injection for 7 days of an S1PR1 selective agonist (SEW2871, 5 mg/kg/day; sham surgery and daily i.p. injection for 7 days of SEW2871 after surgery; LtCCAO and daily i.p. injection for 7 days of SEW2871 and an S1PR1 inverse agonist (VPC23019, 0.5 mg/kg; LtCCAO and daily i.p. injection of DMSO for 7 days after surgery; and sham surgery and daily i.p. injection of DMSO for 7 days. Leptomeningeal anastomoses were visualized 14 days after LtCCAO by latex perfusion method, and a set of animals underwent subsequent permanent middle cerebral artery occlusion (pMCAO 7 days after the treatment termination. Neurological functions 1 hour, 1, 4, and 7 days and infarction volume 7 days after pMCAO were evaluated.In parallel with the increase in S1PR1 mRNA levels, S1PR1 expression colocalized with endothelial cell markers in the leptomeningeal arteries, increased markedly on the side of the CCAO, and peaked 7 days after CCAO. Mitotic cell numbers in the leptomeningeal arteries increased after

  1. Sphingosine-1-Phosphate/Sphingosine-1-Phosphate Receptor 2 Axis Can Promote Mouse and Human Primary Mast Cell Angiogenic Potential through Upregulation of Vascular Endothelial Growth Factor-A and Matrix Metalloproteinase-2

    Alena Chumanevich

    2016-01-01

    Full Text Available Mast cells (MC are present in most vascularized tissues around the vasculature likely exerting immunomodulatory functions. Endowed with diverse mediators, resident MC represent first-line fine-tuners of local microenvironment. Sphingosine-1-phosphate (S1P functions as a pluripotent signaling sphingolipid metabolite in health and disease. S1P formation occurs at low levels in resting MC and is upregulated upon activation. Its export can result in type 2 S1P receptor- (S1PR2- mediated stimulation of MC, further fueling inflammation. However, the role of S1PR2 ligation in proangiogenic vascular endothelial growth factor- (VEGF- A and matrix metalloproteinase- (MMP- 2 release from MC is unknown. Using a preclinical MC-dependent model of acute allergic responses and in vitro stimulated primary mouse bone marrow-derived MC (BMMC or human primary skin MC, we report that S1P signaling resulted in substantial amount of VEGF-A release. Similar experiments using S1pr2-deficient mice or BMMC or selective S1P receptor agonists or antagonists demonstrated that S1P/S1PR2 ligation on MC is important for VEGF-A secretion. Further, we show that S1P stimulation triggered transcriptional upregulation of VEGF-A and MMP-2 mRNA in human but not in mouse MC. S1P exposure also triggered MMP-2 secretion from human MC. These studies identify a novel proangiogenic axis encompassing MC/S1P/S1PR2 likely relevant to inflammation.

  2. Selectivity and specificity of sphingosine-1-phosphate receptor ligands: caveats and critical thinking in characterizing receptor-mediated effects.

    Salomone, Salvatore; Waeber, Christian

    2011-01-01

    Receptors for sphingosine-1-phosphate (S1P) have been identified only recently. Their medicinal chemistry is therefore still in its infancy, and few selective agonists or antagonists are available. Furthermore, the selectivity of S1P receptor agonists or antagonists is not well established. JTE-013 and BML-241 (also known as CAY10444), used extensively as specific S1P(2) and S1P(3) receptors antagonists respectively, are cases in point. When analyzing S1P-induced vasoconstriction in mouse basilar artery, we observed that JTE-013 inhibited not only the effect of S1P, but also the effect of U46619, endothelin-1 or high KCl; JTE-013 strongly inhibited responses to S1P in S1P(2) receptor knockout mice. Similarly, BML-241 has been shown to inhibit increases in intracellular Ca(2+) concentration via P(2) receptor or α(1A)-adrenoceptor stimulation and α(1A)-adrenoceptor-mediated contraction of rat mesenteric artery, while it did not affect S1P(3)-mediated decrease of forskolin-induced cyclic AMP accumulation. Another putative S1P(1/3) receptor antagonist, VPC23019, does not inhibit S1P(3)-mediated vasoconstriction. With these examples in mind, we discuss caveats about relying on available pharmacological tools to characterize receptor subtypes.

  3. Selectivity and specificity of sphingosine-1-phosphate receptor ligands: caveats and critical thinking in characterizing receptor-mediated effects

    Christian eWaeber

    2011-02-01

    Full Text Available Receptors for sphingosine-1-phosphate (S1P have been identified only recently. Their medicinal chemistry is therefore still in its infancy, and few selective agonists or antagonists are available. Furthermore, the selectivity of S1P receptor agonists or antagonists is not well established. JTE-013 and BML-241 (also known as CAY10444, used extensively as specific S1P2 and S1P3 receptors antagonists respectively, are cases in point. When analyzing S1P-induced vasoconstriction in mouse basilar artery, we observed that JTE-013 inhibited not only the effect of S1P, but also the effect of U46619, endothelin-1 or high KCl; JTE-013 strongly inhibited responses to S1P in S1P2 receptor knockout mice. Similarly, BML-241 has been shown to inhibit increases in intracellular Ca2+ concentration via P2 receptor or α1A-adrenoceptor stimulation and α1A-adrenoceptor-mediated contraction of rat mesenteric artery, while it did not affect S1P3-mediated decrease of forskolin-induced cyclic AMP accumulation. Another putative S1P1/3 receptor antagonist, VPC23019, does not inhibit S1P3-mediated vasoconstriction. With these examples in mind, we discuss caveats about relying on available pharmacological tools to characterize receptor subtypes.

  4. HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver

    Ding, Bi-Sen; Liu, Catherine H; Sun, Yue

    2016-01-01

    Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 ...

  5. Impaired endothelial barrier function in apolipoprotein M-deficient mice is dependent on sphingosine-1-phosphate receptor 1

    Christensen, Pernille M; Liu, Catherine H; Swendeman, Steven L

    2016-01-01

    Apolipoprotein M (ApoM) transports sphingosine-1-phosphate (S1P) in plasma, and ApoM-deficient mice (Apom(-/-)) have ∼50% reduced plasma S1P levels. There are 5 known S1P receptors, and S1P induces adherens junction formation between endothelial cells through the S1P1 receptor, which in turn...... suppresses vascular leak. Increased vascular permeability is a hallmark of inflammation. The purpose of this study was to explore the relationships between vascular leakage in ApoM deficiency and S1P1 function in normal physiology and in inflammation. Vascular permeability in the lungs was assessed...... by accumulation of dextran molecules (70 kDa) and was increased ∼40% in Apom(-/-) mice compared to WT (C57Bl6/j) mice. Reconstitution of plasma ApoM/S1P or treatment with an S1P1 receptor agonist (SEW2871) rapidly reversed the vascular leakage to a level similar to that in WT mice, suggesting that it is caused...

  6. Altered expression of sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 in mouse hippocampus after kainic acid treatment

    Lee, Dong Hoon; Jeon, Byeong Tak; Jeong, Eun Ae [Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751 (Korea, Republic of); Kim, Joon Soo; Cho, Yong Woon [Department of Neurosurgery, Masan Samsung Hospital, Sungkyunkwan University School of Medicine, Masan, Gyeongnam 630-723 (Korea, Republic of); Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung [Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751 (Korea, Republic of); Roh, Gu Seob, E-mail: anaroh@gnu.ac.kr [Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751 (Korea, Republic of)

    2010-03-12

    Kainic acid (KA) induces hippocampal cell death and astrocyte proliferation. There are reports that sphingosine kinase (SPHK)1 and sphingosine-1- phosphate (S1P) receptor 1 (S1P{sub 1}) signaling axis controls astrocyte proliferation. Here we examined the temporal changes of SPHK1/S1P{sub 1} in mouse hippocampus during KA-induced hippocampal cell death. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. There was an increase in Fluoro-Jade B-positive cells in the hippocampus of KA-treated mice with temporal changes of glial fibrillary acidic protein (GFAP) expression. The lowest level of SPHK1 protein expression was found 2 h after KA treatment. Six hours after KA treatment, the expression of SPHK1 and S1P{sub 1} proteins steadily increased in the hippocampus. In immunohistochemical analysis, SPHK1 and S1P{sub 1} are more immunoreactive in astrocytes within the hippocampus of KA-treated mice than in hippocampus of control mice. These results indicate that SPHK1/S1P{sub 1} signaling axis may play an important role in astrocytes proliferation during KA-induced excitotoxicity.

  7. Altered expression of sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 in mouse hippocampus after kainic acid treatment

    Lee, Dong Hoon; Jeon, Byeong Tak; Jeong, Eun Ae; Kim, Joon Soo; Cho, Yong Woon; Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung; Roh, Gu Seob

    2010-01-01

    Kainic acid (KA) induces hippocampal cell death and astrocyte proliferation. There are reports that sphingosine kinase (SPHK)1 and sphingosine-1- phosphate (S1P) receptor 1 (S1P 1 ) signaling axis controls astrocyte proliferation. Here we examined the temporal changes of SPHK1/S1P 1 in mouse hippocampus during KA-induced hippocampal cell death. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. There was an increase in Fluoro-Jade B-positive cells in the hippocampus of KA-treated mice with temporal changes of glial fibrillary acidic protein (GFAP) expression. The lowest level of SPHK1 protein expression was found 2 h after KA treatment. Six hours after KA treatment, the expression of SPHK1 and S1P 1 proteins steadily increased in the hippocampus. In immunohistochemical analysis, SPHK1 and S1P 1 are more immunoreactive in astrocytes within the hippocampus of KA-treated mice than in hippocampus of control mice. These results indicate that SPHK1/S1P 1 signaling axis may play an important role in astrocytes proliferation during KA-induced excitotoxicity.

  8. Sphingosine-1-phosphate receptors: Zooming in on ligand-induced intracellular trafficking and its functional implications

    Verzijl, Dennis; Peters, Stephan L. M.; Alewijnse, Astrid E.

    2010-01-01

    Regulatory processes including receptor phosphorylation and intracellular trafficking, also referred to as receptor internalization, are important processes to terminate G protein-coupled receptor (GPCR) signaling. Compelling evidence now indicates that internalization of a receptor is not

  9. Sphingosine-1-phosphate (S1P) displays sustained S1P1 receptor agonism and signaling through S1P lyase-dependent receptor recycling.

    Gatfield, John; Monnier, Lucile; Studer, Rolf; Bolli, Martin H; Steiner, Beat; Nayler, Oliver

    2014-07-01

    The sphingosine-1-phosphate (S1P) type 1 receptor (S1P1R) is a novel therapeutic target in lymphocyte-mediated autoimmune diseases. S1P1 receptor desensitization caused by synthetic S1P1 receptor agonists prevents T-lymphocyte egress from secondary lymphoid organs into the circulation. The selective S1P1 receptor agonist ponesimod, which is in development for the treatment of autoimmune diseases, efficiently reduces peripheral lymphocyte counts and displays efficacy in animal models of autoimmune disease. Using ponesimod and the natural ligand S1P, we investigated the molecular mechanisms leading to different signaling, desensitization and trafficking behavior of S1P1 receptors. In recombinant S1P1 receptor-expressing cells, ponesimod and S1P triggered Gαi protein-mediated signaling and β-arrestin recruitment with comparable potency and efficiency, but only ponesimod efficiently induced intracellular receptor accumulation. In human umbilical vein endothelial cells (HUVEC), ponesimod and S1P triggered translocation of the endogenous S1P1 receptor to the Golgi compartment. However, only ponesimod treatment caused efficient surface receptor depletion, receptor accumulation in the Golgi and degradation. Impedance measurements in HUVEC showed that ponesimod induced only short-lived Gαi protein-mediated signaling followed by resistance to further stimulation, whereas S1P induced sustained Gαi protein-mediated signaling without desensitization. Inhibition of S1P lyase activity in HUVEC rendered S1P an efficient S1P1 receptor internalizing compound and abrogated S1P-mediated sustained signaling. This suggests that S1P lyase - by facilitating S1P1 receptor recycling - is essential for S1P-mediated sustained signaling, and that synthetic agonists are functional antagonists because they are not S1P lyase substrates. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Ablation of sphingosine 1-phosphate receptor subtype 3 impairs hippocampal neuron excitability in vitro and spatial working memory in vivo

    Daniela Weth-Malsch

    2016-11-01

    Full Text Available Understanding the role of the bioactive lipid mediator sphingosine 1-phosphate (S1P within the central nervous system has recently gained more and more attention, as it has been connected to major diseases such as multiple sclerosis and Alzheimer's disease. Even though much data about the functions of the five S1P receptors has been collected for other organ systems, we still lack a complete understanding for their specific roles, in particular within the brain. Therefore, it was the aim of this study to further elucidate the role of S1P receptor subtype 3 (S1P3 in vivo and in vitro with a special focus on the hippocampus. Using an S1P3 knock-out mouse model we applied a range of behavioral tests, performed expression studies and whole cell patch clamp recordings in acute hippocampal slices. We were able to show that S1P3 deficient mice display a significant spatial working memory deficit within the T-maze test, but not in anxiety related tests. Furthermore, S1p3 mRNA was expressed throughout the hippocampal formation. Principal neurons in area CA3 lacking S1P3 showed significantly increased interspike intervals and a significantly decreased input resistance. Upon stimulation with S1P CA3 principal neurons from both wildtype and S1P3-/- mice displayed significantly increased evoked EPSC amplitudes and decay times, whereas rise times remained unchanged. These results suggest a specific involvement of S1P3 for the establishment of spatial working memory and neuronal excitability within the hippocampus.

  11. Induction of antiproliferative connective tissue growth factor expression in Wilms' tumor cells by sphingosine-1-phosphate receptor 2.

    Li, Mei-Hong; Sanchez, Teresa; Pappalardo, Anna; Lynch, Kevin R; Hla, Timothy; Ferrer, Fernando

    2008-10-01

    Connective tissue growth factor (CTGF), a member of the CCN family of secreted matricellular proteins, regulates fibrosis, angiogenesis, cell proliferation, apoptosis, tumor growth, and metastasis. However, the role of CTGF and its regulation mechanism in Wilms' tumor remains largely unknown. We found that the bioactive lipid sphingosine-1-phosphate (S1P) induced CTGF expression in a concentration- and time-dependent manner in a Wilms' tumor cell line (WiT49), whereas FTY720-phosphate, an S1P analogue that binds all S1P receptors except S1P2, did not. Further, the specific S1P2 antagonist JTE-013 completely inhibited S1P-induced CTGF expression, whereas the S1P1 antagonist VPC44116 did not, indicating that this effect was mediated by S1P2. This was confirmed by adenoviral transduction of S1P2 in WiT49 cells, which showed that overexpression of S1P2 increased the expression of CTGF. Induction of CTGF by S1P was sensitive to ROCK inhibitor Y-27632 and c-Jun NH2-terminal kinase inhibitor SP600125, suggesting the requirement of RhoA/ROCK and c-Jun NH2-terminal kinase pathways for S1P-induced CTGF expression. Interestingly, the expression levels of CTGF were decreased in 8 of 10 Wilms' tumor tissues compared with matched normal tissues by quantitative real-time PCR and Western blot analysis. In vitro, human recombinant CTGF significantly inhibited the proliferation of WiT49 cells. In addition, overexpression of CTGF resulted in significant inhibition of WiT49 cell growth. Taken together, these data suggest that CTGF protein induced by S1P2 might act as a growth inhibitor in Wilms' tumor.

  12. Bile Acid-Mediated Sphingosine-1-Phosphate Receptor 2 Signaling Promotes Neuroinflammation during Hepatic Encephalopathy in Mice

    Matthew McMillin

    2017-07-01

    Full Text Available Hepatic encephalopathy (HE is a neuropsychiatric complication that occurs due to deteriorating hepatic function and this syndrome influences patient quality of life, clinical management strategies and survival. During acute liver failure, circulating bile acids increase due to a disruption of the enterohepatic circulation. We previously identified that bile acid-mediated signaling occurs in the brain during HE and contributes to cognitive impairment. However, the influences of bile acids and their downstream signaling pathways on HE-induced neuroinflammation have not been assessed. Conjugated bile acids, such as taurocholic acid (TCA, can activate sphingosine-1-phosphate receptor 2 (S1PR2, which has been shown to promote immune cell infiltration and inflammation in other models. The current study aimed to assess the role of bile-acid mediated S1PR2 signaling in neuroinflammation and disease progression during azoxymethane (AOM-induced HE in mice. Our findings demonstrate a temporal increase of bile acids in the cortex during AOM-induced HE and identified that cortical bile acids were elevated as an early event in this model. In order to classify the specific bile acids that were elevated during HE, a metabolic screen was performed and this assay identified that TCA was increased in the serum and cortex during AOM-induced HE. To reduce bile acid concentrations in the brain, mice were fed a diet supplemented with cholestyramine, which alleviated neuroinflammation by reducing proinflammatory cytokine expression in the cortex compared to the control diet-fed AOM-treated mice. S1PR2 was expressed primarily in neurons and TCA treatment increased chemokine ligand 2 mRNA expression in these cells. The infusion of JTE-013, a S1PR2 antagonist, into the lateral ventricle prior to AOM injection protected against neurological decline and reduced neuroinflammation compared to DMSO-infused AOM-treated mice. Together, this identifies that reducing bile acid

  13. Role of sphingosine 1-phosphate (S1P and effects of fingolimod, an S1P receptor 1 functional antagonist in lymphocyte circulation and autoimmune diseases

    Kenji Chiba

    2014-11-01

    Full Text Available Sphingosine 1-phosphate (S1P, a multi-functional phospholipid mediator, is generated from sphingosine by sphingosine kinases and binds to five known G protein-coupled S1P receptors (S1P1, S1P2, S1P3, S1P4, and S1P5. It is widely accepted that S1P receptor 1 (S1P1 plays an essential role in lymphocyte egress from the secondary lymphoid organs (SLO and thymus, because lymphocyte egress from these organs to periphery is at extremely low levels in mice lacking lymphocytic S1P1. Fingolimod hydrochloride (FTY720 is a first-in-class, orally active S1P1 functional antagonist which was discovered by chemical modification of a natural product, myriocin. Since FTY720 has a structure closely related to sphingosine, the phosphorylated FTY720 (FTY720-P is converted by sphingosine kinases and binds 4 types of S1P receptors. FTY720-P strongly induces down-regulation of S1P1 by internalization and degradation of this receptor and acts as a functional antagonist at S1P1. Consequently, FTY720 inhibits S1P1-dependent lymphocyte egress from the SLO and thymus to reduce circulating lymphocytes including autoreactive Th17 cells, and is highly effective in experimental autoimmune encephalomyelitis (EAE, an animal model of multiple sclerosis (MS. In relapsing remitting MS patients, oral FTY720 shows a superior efficacy when compared to intramuscular interferon-β-1a. Based on these data, it is presumed that modulation of the S1P-S1P1 axis provides an effective therapy for autoimmune diseases including MS.

  14. Sphingosine 1-phosphate and cancer.

    Pyne, Nigel J; El Buri, Ashref; Adams, David R; Pyne, Susan

    2017-09-15

    The bioactive lipid, sphingosine 1-phosphate (S1P) is produced by phosphorylation of sphingosine and this is catalysed by two sphingosine kinase isoforms (SK1 and SK2). Here we discuss structural functional aspects of SK1 (which is a dimeric quaternary enzyme) that relate to coordinated coupling of membrane association with phosphorylation of Ser225 in the 'so-called' R-loop, catalytic activity and protein-protein interactions (e.g. TRAF2, PP2A and G q ). S1P formed by SK1 at the plasma-membrane is released from cells via S1P transporters to act on S1P receptors to promote tumorigenesis. We discuss here an additional novel mechanism that can operate between cancer cells and fibroblasts and which involves the release of the S1P receptor, S1P 2 in exosomes from breast cancer cells that regulates ERK-1/2 signalling in fibroblasts. This novel mechanism of signalling might provide an explanation for the role of S1P 2 in promoting metastasis of cancer cells and which is dependent on the micro-environmental niche. Copyright © 2017. Published by Elsevier Ltd.

  15. Systemic distribution, subcellular localization and differential expression of sphingosine-1-phosphate receptors in benign and malignant human tissues.

    Wang, Chunyi; Mao, Jinghe; Redfield, Samantha; Mo, Yinyuan; Lage, Janice M; Zhou, Xinchun

    2014-10-01

    Five sphingosine-1-phosphate receptors (S1PR): S1PR1, S1PR2, S1PR3, S1PR4 and S1PR5 (S1PR1-5) have been shown to be involved in the proliferation and progression of various cancers. However, none of the S1PRs have been systemically investigated. In this study, we performed immunohistochemistry (IHC) for S1PR1-S1PR5 on different tissues, in order to simultaneously determine the systemic distribution, subcellular localization and expression level of all five S1PRs. We constructed tissue microarrays (TMAs) from 384 formalin-fixed paraffin-embedded (FFPE) blocks containing 183 benign and 201 malignant tissues from 34 human organs/systems. Then we performed IHC for all five S1PRs simultaneously on these TMA slides. The distribution, subcellular localization and expression of each S1PR were determined for each tissue. The data in benign and malignant tissues from the same organ/tissue were then compared using the Student's t-test. In order to reconfirm the subcellular localization of each S1PR as determined by IHC, immunocytochemistry (ICC) was performed on several malignant cell lines. We found that all five S1PRs are widely distributed in multiple human organs/systems. All S1PRs are expressed in both the cytoplasm and nucleus, except S1PR3, whose IHC signals are only seen in the nucleus. Interestingly, the S1PRs are rarely expressed on cellular membranes. Each S1PR is unique in its organ distribution, subcellular localization and expression level in benign and malignant tissues. Among the five S1PRs, S1PR5 has the highest expression level (in either the nucleus or cytoplasm), with S1PR1, 3, 2 and 4 following in descending order. Strong nuclear expression was seen for S1PR1, S1PR3 and S1PR5, whereas S1PR2 and S1PR4 show only weak staining. Four organs/tissues (adrenal gland, liver, brain and colon) show significant differences in IHC scores for the multiple S1PRs (nuclear and/or cytoplasmic), nine (stomach, lymphoid tissues, lung, ovary, cervix, pancreas, skin, soft

  16. Sphingosine-1-phosphate and renal vasoconstriction

    Jensen, Boye L

    2018-01-01

    ) and in conjunction with increased S1P release in pathophysiological situations like sepsis and ischemia-reperfusion incidents, this effect could be relevant in acute kidney injury with parallel decreases in renal blood flow and GFR. This article is protected by copyright. All rights reserved.......In the present issue of Acta Physiologica, Guan et al. in their article "Mechanisms of sphingosine-1-phosphate-mediated vasoconstriction of rat afferent arterioles" (1) address the signaling events associated with sphingosine-1-phosphate (S1P)-mediated renal afferent vasoconstriction and show in......, technically demanding, blood-perfused juxtamedullary nephron preparation that S1P signaling relies predominantly on transmembrane calcium influx from the extracellular fluid through L-type calcium channels with contribution from oxidative stress metabolites(1) . So not only is new information on S1P signaling...

  17. Enhancement of Human Endothelial Cell Adhesion to Type I Collagen by Lysophosphatidic Acid (LPA and Sphingosine-1-Phosphate (S1P

    Hsinyu Lee

    2004-06-01

    Full Text Available The diverse cellular effects of lysophosphatidic acid (LPA and sphingosine-1-phosphate (S1P are transduced by two structurally homologous subfamilies of G protein-coupled receptors, which are encoded by endothelial differentiation genes (Edg Rs. Human umbilical cord vein endothelial cells (HUVECs express Edg Rs for LPA (Edg2 and S1P (Edg1 and 3, which transduce signals for migration of HUVECs through micropore filters coated with type I collagen. Since activation of integrins is essential for optimal migration of endothelial cells, we now examine the capacity of LPA and S1P to augment integrin mediation of endothelial cell binding to type I collagen. Lysophospholipid enhancement of HUVEC adhesion to type I collagen is detectable within 20 minutes. Enhancement of adhesion by both LPA and S1P is significant at 50 nM and optimal at 5µM. Pertussis toxin (PTx, a specific inhibitor of Gi, and C3 exotoxin, a specific inhibitor of Rho, both suppress LPA and S1P enhancement of HUVEC adhesion. In contrast, PD98059, which blocks MAP kinase kinase (MEK, and wortmannin, which inhibits phosphatidylinositol 3-kinase (PI3K, had no effect on LPA- or S1P-enhancement of HUVEC adhesion. Neutralizing monoclonal antibodies specific for α2 and β1 integrin chains, concomitantly decrease LPA and S1P enhancement of HUVEC adhesion to type I collagen. LPA and S1P thus promote type I collagen-dependent adhesion and migration of HUVECs by recruiting α2 and β1 integrin through both Gi and Rho pathways. Integrin α2/β1 therefore appears to be critical on the effects of LPA and S1P on endothelial cell physiology.

  18. Sphingosine 1-Phosphate and Atherosclerosis

    Yatomi, Yutaka

    2018-01-01

    Sphingosine 1-phosphate (S1P) is a potent lipid mediator that works on five kinds of S1P receptors located on the cell membrane. In the circulation, S1P is distributed to HDL, followed by albumin. Since S1P and HDL share several bioactivities, S1P is believed to be responsible for the pleiotropic effects of HDL. Plasma S1P levels are reportedly lower in subjects with coronary artery disease, suggesting that S1P might be deeply involved in the pathogenesis of atherosclerosis. In basic experiments, however, S1P appears to possess both pro-atherosclerotic and anti-atherosclerotic properties; for example, S1P possesses anti-apoptosis, anti-inflammation, and vaso-relaxation properties and maintains the barrier function of endothelial cells, while S1P also promotes the egress and activation of lymphocytes and exhibits pro-thrombotic properties. Recently, the mechanism for the biased distribution of S1P on HDL has been elucidated; apolipoprotein M (apoM) carries S1P on HDL. ApoM is also a modulator of S1P, and the metabolism of apoM-containing lipoproteins largely affects the plasma S1P level. Moreover, apoM modulates the biological properties of S1P. S1P bound to albumin exerts both beneficial and harmful effects in the pathogenesis of atherosclerosis, while S1P bound to apoM strengthens anti-atherosclerotic properties and might weaken the pro-atherosclerotic properties of S1P. Although the detailed mechanisms remain to be elucidated, apoM and S1P might be novel targets for the alleviation of atherosclerotic diseases in the future. PMID:28724841

  19. Analysis of Onset Mechanisms of a Sphingosine 1-Phosphate Receptor Modulator Fingolimod-Induced Atrioventricular Conduction Block and QT-Interval Prolongation

    Yagi, Yukihiro; Nakamura, Yuji; Kitahara, Ken; Harada, Takuma; Kato, Kazuhiko; Ninomiya, Tomohisa; Cao, Xin; Ohara, Hiroshi; Izumi-Nakaseko, Hiroko; Suzuki, Kokichi; Ando, Kentaro

    2014-01-01

    Fingolimod, a sphingosine 1-phosphate (S1P) receptor subtype 1, 3, 4 and 5 modulator, has been used for the treatment of patients with relapsing forms of multiple sclerosis, but atrioventricular conduction block and/or QT-interval prolongation have been reported in some patients after the first dose. In this study, we directly compared the electropharmacological profiles of fingolimod with those of siponimod, a modulator of sphingosine 1-phosphate receptor subtype 1 and 5, using in vivo guinea-pig model and in vitro human ether-a-go-go-related gene (hERG) assay to better understand the onset mechanisms of the clinically observed adverse events. Fingolimod (0.01 and 0.1 mg/kg) or siponimod (0.001 and 0.01 mg/kg) was intravenously infused over 10 min to the halothane-anaesthetized guinea pigs (n = 4), whereas the effects of fingolimod (1 μmol/L) and siponimod (1 μmol/L) on hERG current were examined (n = 3). The high doses of fingolimod and siponimod induced atrioventricular conduction block, whereas the low dose of siponimod prolonged PR interval, which was not observed by that of fingolimod. The high dose of fingolimod prolonged QT interval, which was not observed by either dose of siponimod. Meanwhile, fingolimod significantly inhibited hERG current, which was not observed by siponimod. These results suggest that S1P receptor subtype 1 in the heart could be one of the candidates for fingolimod- and siponimod-induced atrioventricular conduction block since S1P receptor subtype 5 is localized at the brain, and that direct I Kr inhibition may play a key role in fingolimod-induced QT-interval prolongation. - Highlights: • Fingolimod and siponimod are S1P 1,3,4,5 and S1P 1,5 receptor modulators, respectively. • Fingolimod and siponimod induced AV block in the halothane-anesthetized guinea pigs. • S1P 1 in the hearts may be the target of fingolimod- and siponimod-induced AV block. • Fingolimod directly inhibited hERG current, which was not observed by

  20. Analysis of Onset Mechanisms of a Sphingosine 1-Phosphate Receptor Modulator Fingolimod-Induced Atrioventricular Conduction Block and QT-Interval Prolongation

    Yagi, Yukihiro [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567 (Japan); Nakamura, Yuji [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Kitahara, Ken [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Division of Cardiovascular Medicine, Department of Internal Medicine, Faculty of Medicine, Toho University, 6-11-1 Omori-nishi, Ota-ku, Tokyo 143–8541 (Japan); Harada, Takuma [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Kato, Kazuhiko; Ninomiya, Tomohisa [Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567 (Japan); Cao, Xin [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Ohara, Hiroshi [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Division of Cardiovascular Medicine, Department of Internal Medicine, Faculty of Medicine, Toho University, 6-11-1 Omori-nishi, Ota-ku, Tokyo 143–8541 (Japan); Izumi-Nakaseko, Hiroko [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Suzuki, Kokichi [Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567 (Japan); Ando, Kentaro [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); and others

    2014-11-15

    Fingolimod, a sphingosine 1-phosphate (S1P) receptor subtype 1, 3, 4 and 5 modulator, has been used for the treatment of patients with relapsing forms of multiple sclerosis, but atrioventricular conduction block and/or QT-interval prolongation have been reported in some patients after the first dose. In this study, we directly compared the electropharmacological profiles of fingolimod with those of siponimod, a modulator of sphingosine 1-phosphate receptor subtype 1 and 5, using in vivo guinea-pig model and in vitro human ether-a-go-go-related gene (hERG) assay to better understand the onset mechanisms of the clinically observed adverse events. Fingolimod (0.01 and 0.1 mg/kg) or siponimod (0.001 and 0.01 mg/kg) was intravenously infused over 10 min to the halothane-anaesthetized guinea pigs (n = 4), whereas the effects of fingolimod (1 μmol/L) and siponimod (1 μmol/L) on hERG current were examined (n = 3). The high doses of fingolimod and siponimod induced atrioventricular conduction block, whereas the low dose of siponimod prolonged PR interval, which was not observed by that of fingolimod. The high dose of fingolimod prolonged QT interval, which was not observed by either dose of siponimod. Meanwhile, fingolimod significantly inhibited hERG current, which was not observed by siponimod. These results suggest that S1P receptor subtype 1 in the heart could be one of the candidates for fingolimod- and siponimod-induced atrioventricular conduction block since S1P receptor subtype 5 is localized at the brain, and that direct I{sub Kr} inhibition may play a key role in fingolimod-induced QT-interval prolongation. - Highlights: • Fingolimod and siponimod are S1P{sub 1,3,4,5} and S1P{sub 1,5} receptor modulators, respectively. • Fingolimod and siponimod induced AV block in the halothane-anesthetized guinea pigs. • S1P{sub 1} in the hearts may be the target of fingolimod- and siponimod-induced AV block. • Fingolimod directly inhibited hERG current, which was not

  1. Sphingosine-1-Phosphate and the S1P3 Receptor Initiate Neuronal Retraction via RhoA/ROCK Associated with CRMP2 Phosphorylation

    Quarta, Serena; Camprubí-Robles, Maria; Schweigreiter, Rüdiger; Matusica, Dusan; Haberberger, Rainer V.; Proia, Richard L.; Bandtlow, Christine E.; Ferrer-Montiel, Antonio; Kress, Michaela

    2017-01-01

    The bioactive lipid sphingosine-1-phosphate (S1P) is an important regulator in the nervous system. Here, we explored the role of S1P and its receptors in vitro and in preclinical models of peripheral nerve regeneration. Adult sensory neurons and motor neuron-like cells were exposed to S1P in an in vitro assay, and virtually all neurons responded with a rapid retraction of neurites and growth cone collapse which were associated with RhoA and ROCK activation. The S1P1 receptor agonist SEW2871 neither activated RhoA or neurite retraction, nor was S1P-induced neurite retraction mitigated in S1P1-deficient neurons. Depletion of S1P3 receptors however resulted in a dramatic inhibition of S1P-induced neurite retraction and was on the contrary associated with a significant elongation of neuronal processes in response to S1P. Opposing responses to S1P could be observed in the same neuron population, where S1P could activate S1P1 receptors to stimulate elongation or S1P3 receptors and retraction. S1P was, for the first time in sensory neurons, linked to the phosphorylation of collapsin response-mediated protein-2 (CRMP2), which was inhibited by ROCK inhibition. The improved sensory recovery after crush injury further supported the relevance of a critical role for S1P and receptors in fine-tuning axonal outgrowth in peripheral neurons. PMID:29066950

  2. Downregulation of sphingosine 1-phosphate (S1P) receptor 1 by dexamethasone inhibits S1P-induced mesangial cell migration.

    Koch, Alexander; Jäger, Manuel; Völzke, Anja; Grammatikos, Georgios; Zu Heringdorf, Dagmar Meyer; Huwiler, Andrea; Pfeilschifter, Josef

    2015-06-01

    Sphingosine 1-phosphate (S1P) is generated by sphingosine kinase (SK)-1 and -2 and acts mainly as an extracellular ligand at five specific receptors, denoted S1P1-5. After activation, S1P receptors regulate important processes in the progression of renal diseases, such as mesangial cell migration and survival. Previously, we showed that dexamethasone enhances SK-1 activity and S1P formation, which protected mesangial cells from stress-induced apoptosis. Here we demonstrate that dexamethasone treatment lowered S1P1 mRNA and protein expression levels in rat mesangial cells. This effect was abolished in the presence of the glucocorticoid receptor antagonist RU-486. In addition, in vivo studies showed that dexamethasone downregulated S1P1 expression in glomeruli isolated from mice treated with dexamethasone (10 mg/kg body weight). Functionally, we identified S1P1 as a key player mediating S1P-induced mesangial cell migration. We show that dexamethasone treatment significantly lowered S1P-induced migration of mesangial cells, which was again reversed in the presence of RU-486. In summary, we suggest that dexamethasone inhibits S1P-induced mesangial cell migration via downregulation of S1P1. Overall, these results demonstrate that dexamethasone has functional important effects on sphingolipid metabolism and action in renal mesangial cells.

  3. Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-κB ligand (RANKL) expression in rheumatoid arthritis

    Takeshita, Harunori; Kitano, Masayasu; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sato, Chieri; Sekiguchi, Masahiro; Azuma, Naoto; Miyazawa, Keiji; Hla, Timothy; Sano, Hajime

    2012-01-01

    Highlights: ► MH7A cells and CD4 + T cells expressed S1P1 and RANKL. ► S1P increased RANKL expression in MH7A cells and CD4 + T cells. ► The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors. -- Abstract: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-κB ligand (RANKL) in RA synoviocytes and CD4 + T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4 + T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4 + T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-α in MH7A cells and CD4 + T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4 + T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.

  4. Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-{kappa}B ligand (RANKL) expression in rheumatoid arthritis

    Takeshita, Harunori [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Kitano, Masayasu, E-mail: mkitano6@hyo-med.ac.jp [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Iwasaki, Tsuyoshi [Department of Pharmacy, Hyogo University of Health Sciences, 1-3-6 Minatojima Kobe, Hyogo 650-8530 (Japan); Kitano, Sachie; Tsunemi, Sachi; Sato, Chieri; Sekiguchi, Masahiro; Azuma, Naoto [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Miyazawa, Keiji [Discovery Research III, Research and Development, Kissei Pharmaceutical Company, 4365-1 Hodakakashiwara, Azumino, Nagano 399-8304 (Japan); Hla, Timothy [Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, 1300 York Avenue, Box 69, NY 10065 (United States); Sano, Hajime [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer MH7A cells and CD4{sup +} T cells expressed S1P1 and RANKL. Black-Right-Pointing-Pointer S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells. Black-Right-Pointing-Pointer The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors. -- Abstract: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-{kappa}B ligand (RANKL) in RA synoviocytes and CD4{sup +} T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4{sup +} T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-{alpha} in MH7A cells and CD4{sup +} T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4{sup +} T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.

  5. Sphingosine 1-Phosphate (S1P) Receptors 1 and 2 Coordinately Induce Mesenchymal Cell Migration through S1P Activation of Complementary Kinase Pathways*

    Quint, Patrick; Ruan, Ming; Pederson, Larry; Kassem, Moustapha; Westendorf, Jennifer J.; Khosla, Sundeep; Oursler, Merry Jo

    2013-01-01

    Normal bone turnover requires tight coupling of bone resorption and bone formation to preserve bone quantity and structure. With aging and during several pathological conditions, this coupling breaks down, leading to either net bone loss or excess bone formation. To preserve or restore normal bone metabolism, it is crucial to determine the mechanisms by which osteoclasts and osteoblast precursors interact and contribute to coupling. We showed that osteoclasts produce the chemokine sphingosine 1-phosphate (S1P), which stimulates osteoblast migration. Thus, osteoclast-derived S1P may recruit osteoblasts to sites of bone resorption as an initial step in replacing lost bone. In this study we investigated the mechanisms by which S1P stimulates mesenchymal (skeletal) cell chemotaxis. S1P treatment of mesenchymal (skeletal) cells activated RhoA GTPase, but this small G protein did not contribute to migration. Rather, two S1P receptors, S1PR1 and S1PR2, coordinately promoted migration through activation of the JAK/STAT3 and FAK/PI3K/AKT signaling pathways, respectively. These data demonstrate that the chemokine S1P couples bone formation to bone resorption through activation of kinase signaling pathways. PMID:23300082

  6. HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver.

    Ding, Bi-Sen; Liu, Catherine H; Sun, Yue; Chen, Yutian; Swendeman, Steven L; Jung, Bongnam; Chavez, Deebly; Cao, Zhongwei; Christoffersen, Christina; Nielsen, Lars Bo; Schwab, Susan R; Rafii, Shahin; Hla, Timothy

    2016-12-22

    Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 (S1P 1 ) by its natural ligand bound to HDL (HDL-S1P) induces liver regeneration and curtails fibrosis. In mice lacking HDL-S1P, liver regeneration after partial hepatectomy was impeded and associated with aberrant vascular remodeling, thrombosis and peri-sinusoidal fibrosis. Notably, this "maladaptive repair" phenotype was recapitulated in mice that lack S1P 1 in the endothelium. Reciprocally, enhanced plasma levels of HDL-S1P or administration of SEW2871, a pharmacological agonist specific for S1P 1 enhanced regeneration of metabolically functional vasculature and alleviated fibrosis in mouse chronic injury and cholestasis models. This study shows that natural and pharmacological ligands modulate endothelial S1P 1 to stimulate liver regeneration and inhibit fibrosis, suggesting that activation of this pathway may be a novel therapeutic strategy for liver fibrosis.

  7. Sphingosine 1-phosphate as a novel immune regulator of dendritic ...

    Although originally described as an intracellular second messenger, sphingosine 1-phosphate (S1P) has recently been shown to be involved in several physiological and pathological functions as an extracellular mediator. S1P receptors are widely expressed and thought to regulate important functions in cell signalling.

  8. Sphingosine-1-phosphate signaling in the cardiovascular system

    Peters, Stephan L. M.; Alewijnse, Astrid E.

    2007-01-01

    Increasing evidence suggests a key role for the bioactive lipid sphingosine-1-phosphate (S1P) and its G-protein-coupled receptors (S1P(1-5)) in the cardiovascular system. Recent advances in sphingolipid research indicates that cardiomyocyte, vascular smooth muscle and endothelial cell function is

  9. Sphingosine-1-Phosphate (S1P) Signaling in Neural Progenitors.

    Callihan, Phillip; Alqinyah, Mohammed; Hooks, Shelley B

    2018-01-01

    Sphingosine-1-phosphate (S1P) and its receptors are important in nervous system development. Reliable in vitro human model systems are needed to further define specific roles for S1P signaling in neural development. We have described S1P-regulated signaling, survival, and differentiation in a human embryonic stem cell-derived neuroepithelial progenitor cell line (hNP1) that expresses functional S1P receptors. These cells can be further differentiated to a neuronal cell type and therefore represent a good model system to study the role of S1P signaling in human neural development. The following sections describe in detail the culture and differentiation of hNP1 cells and two assays to measure S1P signaling in these cells.

  10. Expansion of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor Function in Normal and Cancer Cells: From Membrane Restructuring to Mediation of Estrogen Signaling and Stem Cell Programming

    2018-01-01

    Sphingolipids, sphingolipid metabolizing enzymes, and their receptors network are being recognized as part of the signaling mechanisms, which govern breast cancer cell growth, migration, and survival during chemotherapy treatment. Approximately 70% of breast cancers are estrogen receptor (ER) positive and, thus, rely on estrogen signaling. Estrogen activates an intracellular network composed of many cytoplasmic and nuclear mediators. Some estrogen effects can be mediated by sphingolipids. Estrogen activates sphingosine kinase 1 (SphK1) and amplifies the intracellular concentration of sphingosine-1-phosphate (S1P) in breast cancer cells during stimulation of proliferation and survival. Specifically, Estrogen activates S1P receptors (S1PR) and induces growth factor receptor transactivation. SphK, S1P, and S1PR expression are causally associated with endocrine resistance and progression to advanced tumor stages in ER-positive breast cancers in vivo. Recently, the network of SphK/S1PR was shown to promote the development of ER-negative cancers and breast cancer stem cells, as well as stimulating angiogenesis. Novel findings confirm and broaden our knowledge about the cross-talk between sphingolipids and estrogen network in normal and malignant cells. Current S1PRs therapeutic inhibition was indicated as a promising chemotherapy approach in non-responsive and advanced malignancies. Considering that sphingolipid signaling has a prominent role in terminally differentiated cells, the impact should be considered when designing specific SphK/S1PR inhibitors. This study analyzes the dynamic of the transformation of sphingolipid axis during a transition from normal to pathological condition on the level of the whole organism. The sphingolipid-based mediation and facilitation of global effects of estrogen were critically accented as a bridging mechanism that should be explored in cancer prevention. PMID:29385066

  11. Expansion of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor Function in Normal and Cancer Cells: From Membrane Restructuring to Mediation of Estrogen Signaling and Stem Cell Programming

    Olga A. Sukocheva

    2018-01-01

    Full Text Available Sphingolipids, sphingolipid metabolizing enzymes, and their receptors network are being recognized as part of the signaling mechanisms, which govern breast cancer cell growth, migration, and survival during chemotherapy treatment. Approximately 70% of breast cancers are estrogen receptor (ER positive and, thus, rely on estrogen signaling. Estrogen activates an intracellular network composed of many cytoplasmic and nuclear mediators. Some estrogen effects can be mediated by sphingolipids. Estrogen activates sphingosine kinase 1 (SphK1 and amplifies the intracellular concentration of sphingosine-1-phosphate (S1P in breast cancer cells during stimulation of proliferation and survival. Specifically, Estrogen activates S1P receptors (S1PR and induces growth factor receptor transactivation. SphK, S1P, and S1PR expression are causally associated with endocrine resistance and progression to advanced tumor stages in ER-positive breast cancers in vivo. Recently, the network of SphK/S1PR was shown to promote the development of ER-negative cancers and breast cancer stem cells, as well as stimulating angiogenesis. Novel findings confirm and broaden our knowledge about the cross-talk between sphingolipids and estrogen network in normal and malignant cells. Current S1PRs therapeutic inhibition was indicated as a promising chemotherapy approach in non-responsive and advanced malignancies. Considering that sphingolipid signaling has a prominent role in terminally differentiated cells, the impact should be considered when designing specific SphK/S1PR inhibitors. This study analyzes the dynamic of the transformation of sphingolipid axis during a transition from normal to pathological condition on the level of the whole organism. The sphingolipid-based mediation and facilitation of global effects of estrogen were critically accented as a bridging mechanism that should be explored in cancer prevention.

  12. ASP4058, a novel agonist for sphingosine 1-phosphate receptors 1 and 5, ameliorates rodent experimental autoimmune encephalomyelitis with a favorable safety profile.

    Rie Yamamoto

    Full Text Available Sphingosine-1-phosphate (S1P is a biologically active sphingolipid that acts through the members of a family of five G protein-coupled receptors (S1P1-S1P5. S1P1 is a major regulator of lymphocyte trafficking, and fingolimod, whose active metabolite fingolimod phosphate acts as a nonselective S1P receptor agonist, exerts its immunomodulatory effect, at least in part, by regulating the lymphocyte trafficking by inducing down regulation of lymphocyte S1P1. Here, we detail the pharmacological profile of 5-{5-[3-(trifluoromethyl-4-{[(2S-1,1,1-trifluoropropan-2-yl]oxy}phenyl]-1,2,4-oxadiazol-3-yl}-1H-benzimidazole (ASP4058, a novel next-generation S1P receptor agonist selective for S1P1 and S1P5. ASP4058 preferentially activates S1P1 and S1P5 compared with S1P2, 3, 4 in GTPγS binding assays in vitro. Oral administration of ASP4058 reduced the number of peripheral lymphocytes and inhibited the development of experimental autoimmune encephalomyelitis (EAE in Lewis rats. Further, ASP4058 prevented relapse of disease in a mouse model of relapsing-remitting EAE. Although these immunomodulatory effects were comparable to those of fingolimod, ASP4058 showed a wider safety margin than fingolimod for bradycardia and bronchoconstriction in rodents. These observations suggest that ASP4058 represents a new therapeutic option for treating multiple sclerosis that is safer than nonselective S1P receptor agonists such as fingolimod.

  13. Roles of sphingosine-1-phosphate (S1P) receptors in malignant behavior of glioma cells. Differential effects of S1P2 on cell migration and invasiveness

    Young, Nicholas; Van Brocklyn, James R.

    2007-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid that signals through a family of five G-protein-coupled receptors, termed S1P 1-5 . S1P stimulates growth and invasiveness of glioma cells, and high expression levels of the enzyme that forms S1P, sphingosine kinase-1, correlate with short survival of glioma patients. In this study we examined the mechanism of S1P stimulation of glioma cell proliferation and invasion by either overexpressing or knocking down, by RNA interference, S1P receptor expression in glioma cell lines. S1P 1 , S1P 2 and S1P 3 all contribute positively to S1P-stimulated glioma cell proliferation, with S1P 1 being the major contributor. Stimulation of glioma cell proliferation by these receptors correlated with activation of ERK MAP kinase. S1P 5 blocks glioma cell proliferation, and inhibits ERK activation. S1P 1 and S1P 3 enhance glioma cell migration and invasion. S1P 2 inhibits migration through Rho activation, Rho kinase signaling and stress fiber formation, but unexpectedly, enhances glioma cell invasiveness by stimulating cell adhesion. S1P 2 also potently enhances expression of the matricellular protein CCN1/Cyr61, which has been implicated in tumor cell adhesion, and invasion as well as tumor angiogenesis. A neutralizing antibody to CCN1 blocked S1P 2 -stimulated glioma invasion. Thus, while S1P 2 decreases glioma cell motility, it may enhance invasion through induction of proteins that modulate glioma cell interaction with the extracellular matrix

  14. Sphingosine 1-phosphate (S1P) induces COX-2 expression and PGE2 formation via S1P receptor 2 in renal mesangial cells.

    Völzke, Anja; Koch, Alexander; Meyer Zu Heringdorf, Dagmar; Huwiler, Andrea; Pfeilschifter, Josef

    2014-01-01

    Understanding the mechanisms of sphingosine 1-phosphate (S1P)-induced cyclooxygenase (COX)-2 expression and prostaglandin E2 (PGE2) formation in renal mesangial cells may provide potential therapeutic targets to treat inflammatory glomerular diseases. Thus, we evaluated the S1P-dependent signaling mechanisms which are responsible for enhanced COX-2 expression and PGE2 formation in rat mesangial cells under basal conditions. Furthermore, we investigated whether these mechanisms are operative in the presence of angiotensin II (Ang II) and of the pro-inflammatory cytokine interleukin-1β (IL-1β). Treatment of rat and human mesangial cells with S1P led to concentration-dependent enhanced expression of COX-2. Pharmacological and molecular biology approaches revealed that the S1P-dependent increase of COX-2 mRNA and protein expression was mediated via activation of S1P receptor 2 (S1P2). Further, inhibition of Gi and p42/p44 MAPK signaling, both downstream of S1P2, abolished the S1P-induced COX-2 expression. In addition, S1P/S1P2-dependent upregulation of COX-2 led to significantly elevated PGE2 levels, which were further potentiated in the presence of Ang II and IL-1β. A functional consequence downstream of S1P/S1P2 signaling is mesangial cell migration that is stimulated by S1P. Interestingly, inhibition of COX-2 by celecoxib and SC-236 completely abolished the migratory response. Overall, our results demonstrate that extracellular S1P induces COX-2 expression via activation of S1P2 and subsequent Gi and p42/p44 MAPK-dependent signaling in renal mesangial cells leading to enhanced PGE2 formation and cell migration that essentially requires COX-2. Thus, targeting S1P/S1P2 signaling pathways might be a novel strategy to treat renal inflammatory diseases. © 2013.

  15. A role of the sphingosine-1-phosphate (S1P)-S1P receptor 2 pathway in epithelial defense against cancer (EDAC).

    Yamamoto, Sayaka; Yako, Yuta; Fujioka, Yoichiro; Kajita, Mihoko; Kameyama, Takeshi; Kon, Shunsuke; Ishikawa, Susumu; Ohba, Yusuke; Ohno, Yusuke; Kihara, Akio; Fujita, Yasuyuki

    2016-02-01

    At the initial step of carcinogenesis, transformation occurs in single cells within epithelia, where the newly emerging transformed cells are surrounded by normal epithelial cells. A recent study revealed that normal epithelial cells have an ability to sense and actively eliminate the neighboring transformed cells, a process named epithelial defense against cancer (EDAC). However, the molecular mechanism of this tumor-suppressive activity is largely unknown. In this study, we investigated a role for the sphingosine-1-phosphate (S1P)-S1P receptor 2 (S1PR2) pathway in EDAC. First, we show that addition of the S1PR2 inhibitor significantly suppresses apical extrusion of RasV12-transformed cells that are surrounded by normal cells. In addition, knockdown of S1PR2 in normal cells induces the same effect, indicating that S1PR2 in the surrounding normal cells plays a positive role in the apical elimination of the transformed cells. Of importance, not endogenous S1P but exogenous S1P is involved in this process. By using FRET analyses, we demonstrate that S1PR2 mediates Rho activation in normal cells neighboring RasV12-transformed cells, thereby promoting accumulation of filamin, a crucial regulator of EDAC. Collectively these data indicate that S1P is a key extrinsic factor that affects the outcome of cell competition between normal and transformed epithelial cells. © 2016 Yamamoto, Yako, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  16. Sphingosine kinase 1/sphingosine-1-phosphate (S1P)/S1P receptor axis is involved in ovarian cancer angiogenesis.

    Dai, Lan; Liu, Yixuan; Xie, Lei; Wu, Xia; Qiu, Lihua; Di, Wen

    2017-09-26

    Sphingosine kinase (SphK)/sphingosine-1-phosphate (S1P)/S1P receptor (S1PR) signaling pathway has been implicated in a variety of pathological processes of ovarian cancer. However, the function of this axis in ovarian cancer angiogenesis remains incompletely defined. Here we provided the first evidence that SphK1/S1P/S1PR 1/3 pathway played key roles in ovarian cancer angiogenesis. The expression level of SphK1, but not SphK2, was closely correlated with the microvascular density (MVD) of ovarian cancer tissue. In vitro , the angiogenic potential and angiogenic factor secretion of ovarian cancer cells could be attenuated by SphK1, but not SphK2, blockage and were restored by the addition of S1P. Moreover, in these cells, we found S1P stimulation induced the angiogenic factor secretion via S1PR 1 and S1PR 3 , but not S1PR 2 . Furthermore, inhibition of S1PR 1/3 , but not S1PR 2 , attenuated the angiogenic potential and angiogenic factor secretion of the cells. in vivo , blockage of SphK or S1PR 1/3 could attenuate ovarian cancer angiogenesis and inhibit angiogenic factor expression in mouse models. Collectively, the current study showed a novel role of SphK1/S1P/S1PR 1/3 axis within the ovarian cancer, suggesting a new target to block ovarian cancer angiogenesis.

  17. Sphingosine 1-phosphate (S1P) suppresses the collagen-induced activation of human platelets via S1P4 receptor.

    Onuma, Takashi; Tanabe, Kumiko; Kito, Yuko; Tsujimoto, Masanori; Uematsu, Kodai; Enomoto, Yukiko; Matsushima-Nishiwaki, Rie; Doi, Tomoaki; Nagase, Kiyoshi; Akamatsu, Shigeru; Tokuda, Haruhiko; Ogura, Shinji; Iwama, Toru; Kozawa, Osamu; Iida, Hiroki

    2017-08-01

    Sphingosine 1-phosphate (S1P) is as an extracellular factor that acts as a potent lipid mediator by binding to specific receptors, S1P receptors (S1PRs). However, the precise role of S1P in human platelets that express S1PRs has not yet been fully clarified. We previously reported that heat shock protein 27 (HSP27) is released from human platelets accompanied by its phosphorylation stimulated by collagen. In the present study, we investigated the effect of S1P on the collagen-induced platelet activation. S1P pretreatment markedly attenuated the collagen-induced aggregation. Co-stimulation with S1P and collagen suppressed collagen-induced platelet activation, but the effect was weaker than that of S1P-pretreatment. The collagen-stimulated secretion of platelet-derived growth factor (PDGF)-AB and the soluble CD40 ligand (sCD40L) release were significantly reduced by S1P. In addition, S1P suppressed the collagen-induced release of HSP27 as well as the phosphorylation of HSP27. S1P significantly suppressed the collagen-induced phosphorylation of p38 mitogen-activated protein kinase. S1P increased the levels of GTP-bound Gαi and GTP-bound Gα13 coupled to S1PPR1 and/or S1PR4. CYM50260, a selective S1PR4 agonist, but not SEW2871, a selective S1PR1 agonist, suppressed the collagen-stimulated platelet aggregation, PDGF-AB secretion and sCD40L release. In addition, CYM50260 reduced the release of phosphorylated-HSP27 by collagen as well as the phosphorylation of HSP27. The selective S1PR4 antagonist CYM50358, which failed to affect collagen-induced HSP27 phosphorylation, reversed the S1P-induced attenuation of HSP27 phosphorylation by collagen. These results strongly suggest that S1P inhibits the collagen-induced human platelet activation through S1PR4 but not S1PR1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Sphingosine kinase/sphingosine 1-phosphate (S1P)/S1P receptor axis is involved in liver fibrosis-associated angiogenesis.

    Yang, Le; Yue, Shi; Yang, Lin; Liu, Xin; Han, Zhen; Zhang, Yuanyuan; Li, Liying

    2013-07-01

    Sphingosine kinase (SphK)/sphingosine 1-phosphate (S1P)/S1P receptor (S1PR) axis is involved in multiple biological processes, including liver fibrosis. Angiogenesis is an important pathophysiological process closely associated with liver fibrosis; however, the functional role of SphK/S1P/S1PR in this process remains incompletely defined. Bile duct ligation or carbon tetrachloride was used to induce liver fibrosis in mice. Human fibrotic samples were obtained from livers of patients undergoing liver transplantation. S1P levels in the liver were examined by HPLC. Expression of angiogenic markers, including angiopoietin 1, CD31, vascular cell adhesion molecule-1, and von Willebrand factor, was characterized by immunofluorescence, real-time RT-PCR, and Western blot in the fibrotic liver and primary mouse hepatic stellate cells (HSCs). SphK inhibitor (SKI) or S1PR antagonists were administered intraperitoneally in mice. S1P levels in the liver were closely correlated with mRNA expression of angiogenic markers. Ang1 is expressed in activated HSCs of the fibrotic liver and in primary HSCs. In HSCs, by using specific antagonists or siRNAs, we demonstrated S1P stimulation induced Ang1 expression via S1PR1 and S1PR3. In vivo, S1P reduction by SKI inhibited angiogenesis in fibrotic mice. Furthermore, S1PR1/3 antagonist significantly blocked upregulation of angiogenic markers in the injured liver, and attenuated the extent of liver fibrosis, while S1PR2 antagonist had no effect on angiogenesis, supporting the key role of S1PR1 and S1PR3 in angiogenesis underlying liver fibrosis process. SphK1/S1P/S1PR1/3 axis plays a crucial role in the angiogenic process required for fibrosis development, which may represent an effective therapeutic strategy for liver fibrosis. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  19. Distinct generation, pharmacology, and distribution of sphingosine 1-phosphate and dihydro-sphingosine 1-phosphate in human neural progenitor cells

    In-vivo and in-vitro studies suggest a crucial role for Sphingosine 1-phosphate (S1P) and its receptors in the development of the nervous system. Dihydrosphingosine 1-phosphate (dhS1P), a reduced form of S1P, is an active ligand at S1P receptors, but the pharmacology and physiology of dhS1P has not...

  20. Sphingosine 1-phosphate lyase enzyme assay using a BODIPY-labeled substrate

    Bandhuvula, Padmavathi; Li Zaiguo; Bittman, Robert; Saba, Julie D.

    2009-01-01

    Sphingosine 1-phosphate lyase (SPL) is responsible for the irreversible catabolism of sphingosine 1-phosphate, which signals through five membrane receptors to mediate cell stress responses, angiogenesis, and lymphocyte trafficking. The standard assay for SPL activity utilizes a radioactive dihydrosphingosine 1-phosphate substrate and is expensive and cumbersome. In this study, we describe an SPL assay that employs an ω-labeled BODIPY-sphingosine 1-phosphate substrate, allowing fluorescent product detection by HPLC and incorporating advantages of the BODIPY fluorophore. The major aldehyde product is confirmed by reaction with 2,4-dinitrophenylhydrazine. The SPL-catalyzed reaction is linear over a 30 min time period and yields a K m of 35 μM for BODIPY-sphingosine 1-phosphate.

  1. Sphingosine-1-Phosphate Signaling in Inflammatory Bowel Disease

    Nielsen, Ole Haagen; Li, Yuan; Lindbom, Bengt Johansson

    2017-01-01

    primary non-responders or lose responsiveness during maintenance treatment. A new class of small molecules, sphingosine-1-phosphate (S1P) receptor modulators, has recently shown efficacy in IBD. Here we provide an overview of the mechanism of action of this novel treatment principle in the context...... of intestinal inflammation. The remarkable impact of therapeutic modulation of the S1P/S1P receptor axis reflects the complexity of the pathogenesis of IBD and the fact that S1P receptor modulation may be a logical therapeutic approach for the future management of IBD....

  2. Association of Sphingosine-1-phosphate (S1P)/S1P Receptor-1 Pathway with Cell Proliferation and Survival in Canine Hemangiosarcoma.

    Rodriguez, A M; Graef, A J; LeVine, D N; Cohen, I R; Modiano, J F; Kim, J-H

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a key biolipid signaling molecule that regulates cell growth and survival, but it has not been studied in tumors from dogs. S1P/S1P1 signaling will contribute to the progression of hemangiosarcoma (HSA). Thirteen spontaneous HSA tissues, 9 HSA cell lines, 8 nonmalignant tissues, including 6 splenic hematomas and 2 livers with vacuolar degeneration, and 1 endothelial cell line derived from a dog with splenic hematoma were used. This was a retrospective case series and in vitro study. Samples were obtained as part of medically necessary diagnostic procedures. Microarray, qRT-PCR, immunohistochemistry, and immunoblotting were performed to examine S1P1 expression. S1P concentrations were measured by high-performance liquid chromatography/mass spectrometry. S1P signaling was evaluated by intracellular Ca(2+) mobilization; proliferation and survival were evaluated using the MTS assay and Annexin V staining. Canine HSA cells expressed higher levels of S1P1 mRNA than nonmalignant endothelial cells. S1P1 protein was present in HSA tissues and cell lines. HSA cells appeared to produce low levels of S1P, but they selectively consumed S1P from the culture media. Exogenous S1P induced an increase in intracellular calcium as well as increased proliferation and viability of HSA cells. Prolonged treatment with FTY720, an inhibitor of S1P1 , decreased S1P1 protein expression and induced apoptosis of HSA cells. S1P/S1P1 signaling pathway functions to maintain HSA cell viability and proliferation. The data suggest that S1P1 or the S1P pathway in general could be targets for therapeutic intervention for dogs with HSA. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  3. Sphingosine 1 Phosphate at the Blood Brain Barrier: Can the Modulation of S1P Receptor 1 Influence the Response of Endothelial Cells and Astrocytes to Inflammatory Stimuli?

    Simona F Spampinato

    Full Text Available The ability of the Blood Brain Barrier (BBB to maintain proper barrier functions, keeping an optimal environment for central nervous system (CNS activity and regulating leukocytes' access, can be affected in CNS diseases. Endothelial cells and astrocytes are the principal BBB cellular constituents and their interaction is essential to maintain its function. Both endothelial cells and astrocytes express the receptors for the bioactive sphingolipid S1P. Fingolimod, an immune modulatory drug whose structure is similar to S1P, has been approved for treatment in multiple sclerosis (MS: fingolimod reduces the rate of MS relapses by preventing leukocyte egress from the lymph nodes. Here, we examined the ability of S1P and fingolimod to act on the BBB, using an in vitro co-culture model that allowed us to investigate the effects of S1P on endothelial cells, astrocytes, and interactions between the two. Acting selectively on endothelial cells, S1P receptor signaling reduced cell death induced by inflammatory cytokines. When acting on astrocytes, fingolimod treatment induced the release of a factor, granulocyte macrophage colony-stimulating factor (GM-CSF that reduced the effects of cytokines on endothelium. In an in vitro BBB model incorporating shear stress, S1P receptor modulation reduced leukocyte migration across the endothelial barrier, indicating a novel mechanism that might contribute to fingolimod efficacy in MS treatment.

  4. Sphingosine 1-Phosphate- and C-C Chemokine Receptor 2-Dependent Activation of CD4+ Plasmacytoid Dendritic Cells in the Bone Marrow Contributes to Signs of Sepsis-Induced Immunosuppression

    Smirnov, Anna; Pohlmann, Stephanie; Nehring, Melanie; Ali, Shafaqat; Mann-Nüttel, Ritu; Scheu, Stefanie; Antoni, Anne-Charlotte; Hansen, Wiebke; Büettner, Manuela; Gardiasch, Miriam J.; Westendorf, Astrid M.; Wirsdörfer, Florian; Pastille, Eva; Dudda, Marcel; Flohé, Stefanie B.

    2017-01-01

    Sepsis is the dysregulated response of the host to systemic, mostly bacterial infection, and is associated with an enhanced susceptibility to life-threatening opportunistic infections. During polymicrobial sepsis, dendritic cells (DCs) secrete enhanced levels of interleukin (IL) 10 due to an altered differentiation in the bone marrow and contribute to the development of immunosuppression. We investigated the origin of the altered DC differentiation using murine cecal ligation and puncture (CLP), a model for human polymicrobial sepsis. Bone marrow cells (BMC) were isolated after sham or CLP operation, the cellular composition was analyzed, and bone marrow-derived DCs (BMDCs) were generated in vitro. From 24 h on after CLP, BMC gave rise to BMDC that released enhanced levels of IL-10. In parallel, a population of CD11chiMHCII+CD4+ DCs expanded in the bone marrow in a MyD88-dependent manner. Prior depletion of the CD11chiMHCII+CD4+ DCs from BMC in vitro reversed the increased IL-10 secretion of subsequently differentiating BMDC. The expansion of the CD11chiMHCII+CD4+ DC population in the bone marrow after CLP required the function of sphingosine 1-phosphate receptors and C-C chemokine receptor (CCR) 2, the receptor for C-C chemokine ligand (CCL) 2, but was not associated with monocyte mobilization. CD11chiMHCII+CD4+ DCs were identified as plasmacytoid DCs (pDCs) that had acquired an activated phenotype according to their increased expression of MHC class II and CD86. A redistribution of CD4+ pDCs from MHC class II− to MHC class II+ cells concomitant with enhanced expression of CD11c finally led to the rise in the number of CD11chiMHCII+CD4+ DCs. Enhanced levels of CCL2 were found in the bone marrow of septic mice and the inhibition of CCR2 dampened the expression of CD86 on CD4+ pDCs after CLP in vitro. Depletion of pDCs reversed the bias of splenic DCs toward increased IL-10 synthesis after CLP in vivo. Thus, during polymicrobial sepsis, CD4+ pDCs are activated

  5. Sphingosine 1-Phosphate- and C-C Chemokine Receptor 2-Dependent Activation of CD4+ Plasmacytoid Dendritic Cells in the Bone Marrow Contributes to Signs of Sepsis-Induced Immunosuppression

    Anna Smirnov

    2017-11-01

    Full Text Available Sepsis is the dysregulated response of the host to systemic, mostly bacterial infection, and is associated with an enhanced susceptibility to life-threatening opportunistic infections. During polymicrobial sepsis, dendritic cells (DCs secrete enhanced levels of interleukin (IL 10 due to an altered differentiation in the bone marrow and contribute to the development of immunosuppression. We investigated the origin of the altered DC differentiation using murine cecal ligation and puncture (CLP, a model for human polymicrobial sepsis. Bone marrow cells (BMC were isolated after sham or CLP operation, the cellular composition was analyzed, and bone marrow-derived DCs (BMDCs were generated in vitro. From 24 h on after CLP, BMC gave rise to BMDC that released enhanced levels of IL-10. In parallel, a population of CD11chiMHCII+CD4+ DCs expanded in the bone marrow in a MyD88-dependent manner. Prior depletion of the CD11chiMHCII+CD4+ DCs from BMC in vitro reversed the increased IL-10 secretion of subsequently differentiating BMDC. The expansion of the CD11chiMHCII+CD4+ DC population in the bone marrow after CLP required the function of sphingosine 1-phosphate receptors and C-C chemokine receptor (CCR 2, the receptor for C-C chemokine ligand (CCL 2, but was not associated with monocyte mobilization. CD11chiMHCII+CD4+ DCs were identified as plasmacytoid DCs (pDCs that had acquired an activated phenotype according to their increased expression of MHC class II and CD86. A redistribution of CD4+ pDCs from MHC class II− to MHC class II+ cells concomitant with enhanced expression of CD11c finally led to the rise in the number of CD11chiMHCII+CD4+ DCs. Enhanced levels of CCL2 were found in the bone marrow of septic mice and the inhibition of CCR2 dampened the expression of CD86 on CD4+ pDCs after CLP in vitro. Depletion of pDCs reversed the bias of splenic DCs toward increased IL-10 synthesis after CLP in vivo. Thus, during polymicrobial sepsis, CD4+ pDCs are

  6. PPARγ agonists upregulate sphingosine 1-phosphate (S1P) receptor 1 expression, which in turn reduces S1P-induced [Ca(2+)]i increases in renal mesangial cells.

    Koch, Alexander; Völzke, Anja; Puff, Bianca; Blankenbach, Kira; Meyer Zu Heringdorf, Dagmar; Huwiler, Andrea; Pfeilschifter, Josef

    2013-11-01

    We previously identified peroxisome proliferator-activated receptor gamma (PPARγ) agonists (thiazolidinediones, TZDs) as modulators of the sphingolipid metabolism in renal mesangial cells. TZDs upregulated sphingosine kinase 1 (SK-1) and increased the formation of intracellular sphingosine 1-phosphate (S1P), which in turn reduced the expression of pro-fibrotic connective tissue growth factor. Since S1P also acts as extracellular ligand at specific S1P receptors (S1PR, S1P1-5), we investigated here the effect of TZDs on S1PR expression in mesangial cells and evaluated the functional consequences by measuring S1P-induced increases in intracellular free Ca(2+) concentration ([Ca(2+)]i). Treatment with two different TZDs, troglitazone and rosiglitazone, enhanced S1P1 mRNA and protein expression in rat mesangial cells, whereas S1P2-5 expression levels were not altered. Upregulation of S1P1 mRNA upon TZD treatment was also detected in human mesangial cells and mouse glomeruli. PPARγ antagonism and promoter studies revealed that the TZD-dependent S1P1 mRNA induction involved a functional PPAR response element in the S1P1 promoter. Pharmacological approaches disclosed that S1P-induced [Ca(2+)]i increases in rat mesangial cells were predominantly mediated by S1P2 and S1P3. Interestingly, the transcriptional upregulation of S1P1 by TZDs resulted in a reduction of S1P-induced [Ca(2+)]i increases, which was reversed by the S1P1/3 antagonist VPC-23019, the protein kinase C (PKC) inhibitor PKC-412, and by S1P1 siRNA. These data suggest that PPARγ-dependent upregulation of S1P1 leads to an inhibition of S1P-induced Ca(2+) signaling in a PKC-dependent manner. Overall, these results reveal that TZDs not only modulate intracellular S1P levels but also regulate S1PR signaling by increasing S1P1 expression in mesangial cells. © 2013.

  7. Sphingosine-1-phosphate stimulates rat primary chondrocyte proliferation

    Kim, Mi-Kyoung; Lee, Ha Young; Kwak, Jong-Young; Park, Joo-In; Yun, Jeanho; Bae, Yoe-Sik

    2006-01-01

    Rat primary chondrocytes express the sphingosine-1-phosphate (S1P) receptor, S1P 2 , S1P 3 , S1P 4 , but not S1P 1 . When chondrocytes were stimulated with S1P or phytosphingosine-1-phosphate (PhS1P, an S1P 1 - and S1P 4 -selective agonist), phospholipase C-mediated cytosolic calcium increase was dramatically induced. S1P and PhS1P also stimulated two kinds of mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK) and p38 kinase in chondrocytes. In terms of the two phospholipids-mediated functional modulation of chondrocytes, S1P and PhS1P stimulated cellular proliferation. The two phospholipids-induced chondrocyte proliferations were almost completely blocked by PD98059 but not by SB203580, suggesting that ERK but not p38 kinase is essentially required for the proliferation. Pertussis toxin almost completely inhibited the two phospholipids-induced cellular proliferation and ERK activation, indicating the crucial role of G i protein. This study demonstrates the physiological role of two important phospholipids (S1P and PhS1P) on the modulation of rat primary chondrocyte proliferation, and the crucial role played by ERK in the process

  8. The signaling lipid sphingosine 1-phosphate regulates mechanical pain

    Hill, Rose Z; Hoffman, Benjamin U; Morita, Takeshi; Campos, Stephanie M; Lumpkin, Ellen A; Brem, Rachel B

    2018-01-01

    Somatosensory neurons mediate responses to diverse mechanical stimuli, from innocuous touch to noxious pain. While recent studies have identified distinct populations of A mechanonociceptors (AMs) that are required for mechanical pain, the molecular underpinnings of mechanonociception remain unknown. Here, we show that the bioactive lipid sphingosine 1-phosphate (S1P) and S1P Receptor 3 (S1PR3) are critical regulators of acute mechanonociception. Genetic or pharmacological ablation of S1PR3, or blockade of S1P production, significantly impaired the behavioral response to noxious mechanical stimuli, with no effect on responses to innocuous touch or thermal stimuli. These effects are mediated by fast-conducting A mechanonociceptors, which displayed a significant decrease in mechanosensitivity in S1PR3 mutant mice. We show that S1PR3 signaling tunes mechanonociceptor excitability via modulation of KCNQ2/3 channels. Our findings define a new role for S1PR3 in regulating neuronal excitability and establish the importance of S1P/S1PR3 signaling in the setting of mechanical pain thresholds. PMID:29561262

  9. Cardiovascular effects of sphingosine-1-phosphate and other sphingomyelin metabolites

    Alewijnse, Astrid E.; Peters, Stephan L. M.; Michel, Martin C.

    2004-01-01

    1 Upon various stimuli, cells metabolize sphingomyelin from the cellular plasma membrane to form sphingosylphosphorylcholine (SPC) or ceramide. The latter can be further metabolized to sphingosine and then sphingosine-1-phosphate (S1P). Apart from local formation, S1P and SPC are major constituents

  10. sphingosine-1-phosphate transport and its role in immunology

    Reitsema, V.; Bouma, Hjalmar; Kok, Jan

    2014-01-01

    Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite with many important functions in cellular and systemic physiology, including the immune system. As it cannot traverse the membrane, it is exported from cells by transporters. Several members of the ATP-binding cassette (ABC) transporter

  11. Sphingosine 1-Phosphate and Cancer: Lessons from Thyroid Cancer Cells

    Kid Törnquist

    2013-05-01

    Full Text Available Sphingomyelin is found in the cell membrane of all eukaryotic cells, and was for a long time considered merely as a structural component. However, during the last two decades, metabolites of sphingomyelin, especially sphingosine 1-phosphate (S1P, have proven to be physiologically significant regulators of cell function. Through its five different G protein-coupled receptors, S1P regulates a wide array of cellular processes, ranging from stimulating cellular proliferation and migration, to the inhibition of apoptosis and induction of angiogenesis and modulation of cellular calcium homeostasis. Many of the processes regulated by S1P are important for normal cell physiology, but may also induce severe pathological conditions, especially in malignancies like cancer. Thus, understanding S1P signaling mechanisms has been the aim of a multitude of investigations. Great interest has also been shown in understanding the action of sphingosine kinase (SphK, i.e., the kinase phosphorylating sphingosine to S1P, and the interactions between S1P and growth factor signaling. In the present review, we will discuss recent findings regarding the possible importance of S1P and SphK in the etiology of thyroid cancer. Although clinical data is still scarce, our in vitro findings suggest that S1P may function as a “double-edged sword”, as the receptor profile of thyroid cancer cells largely determines whether S1P stimulates or blocks cellular migration. We will also discuss the interactions between S1P- and VEGF-evoked signaling, and the importance of a S1P1-VEGF receptor 2 complex in thyroid cancer cells.

  12. In vitro and in vivo study of endothelial cells radio-induced death modulation by Sphingosine-1-Phosphate; Etude in vitro et in vivo de la regulation de la mort radioinduite des cellules endotheliales par la Sphingosine-1-Phosphate

    Bonnaud, St

    2007-01-15

    Protecting the vasculature from radiation-induced death is a major concern in tissue radioprotection. Developing a model of endothelial cells radiosensitivity, we proved that HMEC-1 undergo 2 waves of death after exposure to 15 Gy: an early pre mitotic apoptosis dependent of ceramide generation and a delayed DNA damage-induced mitotic death. Sphingosine-1-Phosphate (S1P), a ceramide antagonist, protects HMEC-1 only from early apoptosis, but not from mitotic death. We confirmed in vivo the S1P radioprotection from ceramide-mediated radio-induced apoptosis, and that S1P radioprotection is partially mediated by S1Ps receptors. Segregation between these 2 types of death may give the opportunity to define a new class of radioprotectors for normal tissue where quiescent endothelium represent the most sensitive target, while excluding malignant tumor containing pro-proliferating angiogenic endothelial cells, sensitive to mitotic death. (author)

  13. Sphingosine 1-phosphate (S1P) signaling in glioblastoma multiforme-A systematic review.

    Mahajan-Thakur, Shailaja; Bien-Möller, Sandra; Marx, Sascha; Schroeder, Henry; Rauch, Bernhard H

    2017-11-17

    The multifunctional sphingosine-1-phosphate (S1P) is a lipid signaling molecule and central regulator in the development of several cancer types. In recent years, intriguing information has become available regarding the role of S1P in the progression of Glioblastoma multiforme (GBM), the most aggressive and common brain tumor in adults. S1P modulates numerous cellular processes in GBM, such as oncogenesis, proliferation and survival, invasion, migration, metastasis and stem cell behavior. These processes are regulated via a family of five G-protein-coupled S1P receptors (S1PR1-5) and may involve mainly unknown intracellular targets. Distinct expression patterns and multiple intracellular signaling pathways of each S1PR subtype enable S1P to exert its pleiotropic cellular actions. Several studies have demonstrated alterations in S1P levels, the involvement of S1PRs and S1P metabolizing enzymes in GBM pathophysiology. While the tumorigenic actions of S1P involve the activation of several kinases and transcription factors, the specific G-protein (Gi, Gq, and G12/13)-coupled signaling pathways and downstream mediated effects in GBM remain to be elucidated in detail. This review summarizes the recent findings concerning the role of S1P and its receptors in GBM. We further highlight the current insights into the signaling pathways considered fundamental for regulating the cellular processes in GMB and ultimately patient prognosis.

  14. In vitro and in vivo study of endothelial cells radio-induced death modulation by Sphingosine-1-Phosphate

    Bonnaud, St.

    2007-01-01

    Protecting the vasculature from radiation-induced death is a major concern in tissue radioprotection. Developing a model of endothelial cells radiosensitivity, we proved that HMEC-1 undergo 2 waves of death after exposure to 15 Gy: an early pre mitotic apoptosis dependent of ceramide generation and a delayed DNA damage-induced mitotic death. Sphingosine-1-Phosphate (S1P), a ceramide antagonist, protects HMEC-1 only from early apoptosis, but not from mitotic death. We confirmed in vivo the S1P radioprotection from ceramide-mediated radio-induced apoptosis, and that S1P radioprotection is partially mediated by S1Ps receptors. Segregation between these 2 types of death may give the opportunity to define a new class of radioprotectors for normal tissue where quiescent endothelium represent the most sensitive target, while excluding malignant tumor containing pro-proliferating angiogenic endothelial cells, sensitive to mitotic death. (author)

  15. Controlled release of sphingosine-1-phosphate agonist with gelatin hydrogels for macrophage recruitment.

    Murakami, Masahiro; Saito, Takashi; Tabata, Yasuhiko

    2014-11-01

    The objective of this study is to design a drug delivery system (DDS) for the in vivo promotion of macrophage recruitment. As the drug, a water-insoluble agonist of sphingosine-1-phosphate type 1 receptor (SEW2871) was selected. SEW2871 (SEW) was water-solubilized by micelle formation with gelatin grafted by L-lactic acid oligomer. SEW micelles were mixed with gelatin, followed by dehydrothermal crosslinking of gelatin to obtain gelatin hydrogels incorporating SEW micelles. SEW was released from the hydrogels incorporating SEW micelles in vitro and in vivo. The water-solubilized SEW showed in vitro macrophage migration activity. When implanted into the back subcutis or the skin wound defect of mice, the hydrogel incorporating SEW micelles promoted macrophage migration toward the tissue around the implanted site to a significantly great extent compared with SEW-free hydrogel and that mixed with SEW micelles. The hydrogel is a promising DDS to enhance macrophage recruitment in vivo. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Sphingosine-1-phosphate signalling induces the production of Lcn-2 by macrophages to promote kidney regeneration

    Sola, Anna; Weigert, Andreas; Jung, Michaela

    2011-01-01

    the kidney. The present study describes a mechanism for renal tissue regeneration after ischaemia/reperfusion injury. Following injury, apoptotic cell-derived sphingosine-1-phosphate (S1P) or exogenously administered sphingosine analogue FTY720 activates macrophages to support the proliferation and healing...... of renal epithelium, once inflammatory conditions are terminated. Both suppression of inflammation and renal regeneration might require S1P receptor 3 (S1P3) signalling and downstream release of neutrophil gelatinase-associated lipocalin (NGAL/Lcn-2) from macrophages. Overall, our data point...

  17. Sphingosine-1-Phosphate Evokes Unique Segment-Specific Vasoconstriction of the Renal Microvasculature

    Singletary, Sean T.; Cook, Anthony K.; Hobbs, Janet L.; Pollock, Jennifer S.; Inscho, Edward W.

    2014-01-01

    Sphingosine-1-phosphate (S1P), a bioactive sphingolipid metabolite, has been implicated in regulating vascular tone and participating in chronic and acute kidney injury. However, little is known about the role of S1P in the renal microcirculation. Here, we directly assessed the vasoresponsiveness of preglomerular and postglomerular microvascular segments to exogenous S1P using the in vitro blood-perfused juxtamedullary nephron preparation. Superfusion of S1P (0.001–10 μM) evoked concentration-dependent vasoconstriction in preglomerular microvessels, predominantly afferent arterioles. After administration of 10 μM S1P, the diameter of afferent arterioles decreased to 35%±5% of the control diameter, whereas the diameters of interlobular and arcuate arteries declined to 50%±12% and 68%±6% of the control diameter, respectively. Notably, efferent arterioles did not respond to S1P. The S1P receptor agonists FTY720 and FTY720-phosphate and the specific S1P1 receptor agonist SEW2871 each evoked modest afferent arteriolar vasoconstriction. Conversely, S1P2 receptor inhibition with JTE-013 significantly attenuated S1P-mediated afferent arteriolar vasoconstriction. Moreover, blockade of L-type voltage-dependent calcium channels with diltiazem or nifedipine attenuated S1P-mediated vasoconstriction. Intravenous injection of S1P in anesthetized rats reduced renal blood flow dose dependently. Western blotting and immunofluorescence revealed S1P1 and S1P2 receptor expression in isolated preglomerular microvessels and microvascular smooth muscle cells. These data demonstrate that S1P evokes segmentally distinct preglomerular vasoconstriction via activation of S1P1 and/or S1P2 receptors, partially via L-type voltage-dependent calcium channels. Accordingly, S1P may have a novel function in regulating afferent arteriolar resistance under physiologic conditions. PMID:24578134

  18. Cellular function and signaling pathways of vascular smooth muscle cells modulated by sphingosine 1-phosphate

    Takuji Machida

    2016-12-01

    Full Text Available Sphingosine 1-phosphate (S1P plays important roles in cardiovascular pathophysiology. S1P1 and/or S1P3, rather than S1P2 receptors, seem to be predominantly expressed in vascular endothelial cells, while S1P2 and/or S1P3, rather than S1P1 receptors, seem to be predominantly expressed in vascular smooth muscle cells (VSMCs. S1P has multiple actions, such as proliferation, inhibition or stimulation of migration, and vasoconstriction or release of vasoactive mediators. S1P induces an increase of the intracellular Ca2+ concentration in many cell types, including VSMCs. Activation of S1P3 seems to play an important role in Ca2+ mobilization. S1P induces cyclooxygenase-2 expression in VSMCs via both S1P2 and S1P3 receptors. S1P2 receptor activation in VSMCs inhibits inducible nitric oxide synthase (iNOS expression. At the local site of vascular injury, vasoactive mediators such as prostaglandins and NO produced by VSMCs are considered primarily as a defensive and compensatory mechanism for the lack of endothelial function to prevent further pathology. Therefore, selective S1P2 receptor antagonists may have the potential to be therapeutic agents, in view of their antagonism of iNOS inhibition by S1P. Further progress in studies of the precise mechanisms of S1P may provide useful knowledge for the development of new S1P-related drugs for the treatment of cardiovascular diseases.

  19. Vitamin D attenuates sphingosine-1-phosphate (S1P)-mediated inhibition of extravillous trophoblast migration.

    Westwood, Melissa; Al-Saghir, Khiria; Finn-Sell, Sarah; Tan, Cherlyn; Cowley, Elizabeth; Berneau, Stéphane; Adlam, Daman; Johnstone, Edward D

    2017-12-01

    Failure of trophoblast invasion and remodelling of maternal blood vessels leads to the pregnancy complication pre-eclampsia (PE). In other systems, the sphingolipid, sphingosine-1-phosphate (S1P), controls cell migration therefore this study determined its effect on extravillous trophoblast (EVT) function. A transwell migration system was used to assess the behaviour of three trophoblast cell lines, Swan-71, SGHPL-4, and JEG3, and primary human trophoblasts in the presence or absence of S1P, S1P pathway inhibitors and 1,25(OH) 2 D 3 . QPCR and immunolocalisation were used to demonstrate EVT S1P receptor expression. EVTs express S1P receptors 1, 2 and 3. S1P inhibited EVT migration. This effect was abolished in the presence of the specific S1PR2 inhibitor, JTE-013 (p S1P alone) whereas treatment with the S1R1/3 inhibitor, FTY720, had no effect. In other cell types S1PR2 is regulated by vitamin D; here we found that treatment with 1,25(OH) 2 D 3 for 48 or 72 h reduces S1PR2 (4-fold; S1P did not inhibit the migration of cells exposed to 1,25(OH) 2 D 3 (p S1P receptor isoforms, S1P predominantly signals through S1PR2/Gα 12/13 to activate Rho and thereby acts as potent inhibitor of EVT migration. Importantly, expression of S1PR2, and therefore S1P function, can be down-regulated by vitamin D. Our data suggest that vitamin D deficiency, which is known to be associated with PE, may contribute to the impaired trophoblast migration that underlies this condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Sphingosine-1-Phosphate Is a Novel Regulator of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR Activity.

    Firhan A Malik

    Full Text Available The cystic fibrosis transmembrane conductance regulator (CFTR attenuates sphingosine-1-phosphate (S1P signaling in resistance arteries and has emerged as a prominent regulator of myogenic vasoconstriction. This investigation demonstrates that S1P inhibits CFTR activity via adenosine monophosphate-activated kinase (AMPK, establishing a potential feedback link. In Baby Hamster Kidney (BHK cells expressing wild-type human CFTR, S1P (1μmol/L attenuates forskolin-stimulated, CFTR-dependent iodide efflux. S1P's inhibitory effect is rapid (within 30 seconds, transient and correlates with CFTR serine residue 737 (S737 phosphorylation. Both S1P receptor antagonism (4μmol/L VPC 23019 and AMPK inhibition (80μmol/L Compound C or AMPK siRNA attenuate S1P-stimluated (i AMPK phosphorylation, (ii CFTR S737 phosphorylation and (iii CFTR activity inhibition. In BHK cells expressing the ΔF508 CFTR mutant (CFTRΔF508, the most common mutation causing cystic fibrosis, both S1P receptor antagonism and AMPK inhibition enhance CFTR activity, without instigating discernable correction. In summary, we demonstrate that S1P/AMPK signaling transiently attenuates CFTR activity. Since our previous work positions CFTR as a negative S1P signaling regulator, this signaling link may positively reinforce S1P signals. This discovery has clinical ramifications for the treatment of disease states associated with enhanced S1P signaling and/or deficient CFTR activity (e.g. cystic fibrosis, heart failure. S1P receptor/AMPK inhibition could synergistically enhance the efficacy of therapeutic strategies aiming to correct aberrant CFTR trafficking.

  1. Pancreas lineage allocation and specification are regulated by sphingosine-1-phosphate signalling

    Serafimidis, Ioannis; Rodriguez-Aznar, Eva; Lesche, Mathias; Yoshioka, Kazuaki; Takuwa, Yoh; Dahl, Andreas; Pan, Duojia; Gavalas, Anthony

    2017-01-01

    During development, progenitor expansion, lineage allocation, and implementation of differentiation programs need to be tightly coordinated so that different cell types are generated in the correct numbers for appropriate tissue size and function. Pancreatic dysfunction results in some of the most debilitating and fatal diseases, including pancreatic cancer and diabetes. Several transcription factors regulating pancreas lineage specification have been identified, and Notch signalling has been implicated in lineage allocation, but it remains unclear how these processes are coordinated. Using a combination of genetic approaches, organotypic cultures of embryonic pancreata, and genomics, we found that sphingosine-1-phosphate (S1p), signalling through the G protein coupled receptor (GPCR) S1pr2, plays a key role in pancreas development linking lineage allocation and specification. S1pr2 signalling promotes progenitor survival as well as acinar and endocrine specification. S1pr2-mediated stabilisation of the yes-associated protein (YAP) is essential for endocrine specification, thus linking a regulator of progenitor growth with specification. YAP stabilisation and endocrine cell specification rely on Gαi subunits, revealing an unexpected specificity of selected GPCR intracellular signalling components. Finally, we found that S1pr2 signalling posttranscriptionally attenuates Notch signalling levels, thus regulating lineage allocation. Both S1pr2-mediated YAP stabilisation and Notch attenuation are necessary for the specification of the endocrine lineage. These findings identify S1p signalling as a novel key pathway coordinating cell survival, lineage allocation, and specification and linking these processes by regulating YAP levels and Notch signalling. Understanding lineage allocation and specification in the pancreas will shed light in the origins of pancreatic diseases and may suggest novel therapeutic approaches. PMID:28248965

  2. Plasma levels of sphingosine-1-phosphate and apolipoprotein M in patients with monogenic disorders of HDL metabolism

    Karuna, Ratna; Park, Rebekka; Othman, Alaa; Holleboom, Adriaan G.; Motazacker, Mohammad Mahdi; Sutter, Iryna; Kuivenhoven, Jan Albert; Rohrer, Lucia; Matile, Hugues; Hornemann, Thorsten; Stoffel, Markus; Rentsch, Katharina M.; von Eckardstein, Arnold

    2011-01-01

    Apolipoprotein M (apoM) has been identified as a specific sphingosine-1-phosphate (S1P) binding protein of HDL. To investigate the in vivo effects of disturbed apoM or HDL metabolism we quantified S1P and apoM in plasmas of wild-type, apoM-knock-out, and apoM transgenic mice as well as 50 patients

  3. Electrophysiological and functional effects of sphingosine-1-phosphate in mouse ventricular fibroblasts

    Benamer, Najate; Fares, Nassim; Bois, Patrick; Faivre, Jean-Francois

    2011-01-01

    Highlights: → In cardiac fibroblasts, SUR2/Kir6.1 channel is activated by S1P via the S1P3R. → S1P increases cell proliferation through SUR2/Kir6.1 activation. → S1P decreases collagen and IL-6 secretion through SUR2/Kir6.1 activation. → S1P stimulates fibroblast migration independently from SUR2/Kir6.1 channel. -- Abstract: The aim of this study was to characterize the effects of sphingosine-1-phosphate (S1P) on cardiac ventricular fibroblasts. Impacts of S1P on fibroblast excitability, cell migration, proliferation and secretion were characterized. The patch-clamp technique in the whole-cell configuration was used to study the S1P-induced current from mouse ventricular fibroblasts. The expression level of the S1P receptor during cell culture duration was evaluated by western-blot. Fibroblast proliferation and migration were quantified using the methylene blue assay and the Boyden chamber technique, respectively. Finally, fibroblast secretion properties were estimated by quantification of the IL-6 and collagen levels using ELISA and SIRCOL collagen assays, respectively. We found that S1P activated SUR2/Kir6.1 channel and that this effect was sensitive to specific inhibition of the S1P receptor of type 3 (S1P3R). In contrast, S1P1R receptor inhibition had no effect. Moreover, the S1P-induced current increased with cell culture duration whereas S1P3R expression level remained constant. The activation of SUR2/Kir6.1 channel by S1P via S1P3R stimulated cell proliferation and decreased IL-6 and collagen secretions. S1P also stimulated fibroblast migration via S1P3R but independently from SUR2/Kir6.1 channel activation. This study demonstrates that S1P, via S1P3R, affects cardiac ventricular fibroblasts function independently or through activation of SUR2/Kir6.1 channel. The latter effect occurs after fibroblasts differentiate into myofibroblasts, opening a new potential therapeutic strategy to modulate fibrosis after cardiac physiopathological injury.

  4. Electrophysiological and functional effects of sphingosine-1-phosphate in mouse ventricular fibroblasts

    Benamer, Najate [UMR CNRS/Universite de Poitiers No. 6187, Pole Biologie Sante Bat B36, BP 633, 1 rue Georges Bonnet, 86022 Poitiers (France); Fares, Nassim [Laboratoire de Physiologie, Faculte de Medecine, Universite Saint Joseph, Beyrouth (Lebanon); Bois, Patrick [UMR CNRS/Universite de Poitiers No. 6187, Pole Biologie Sante Bat B36, BP 633, 1 rue Georges Bonnet, 86022 Poitiers (France); Faivre, Jean-Francois, E-mail: Jean-Francois.Faivre@univ-poitiers.fr [UMR CNRS/Universite de Poitiers No. 6187, Pole Biologie Sante Bat B36, BP 633, 1 rue Georges Bonnet, 86022 Poitiers (France)

    2011-04-29

    Highlights: {yields} In cardiac fibroblasts, SUR2/Kir6.1 channel is activated by S1P via the S1P3R. {yields} S1P increases cell proliferation through SUR2/Kir6.1 activation. {yields} S1P decreases collagen and IL-6 secretion through SUR2/Kir6.1 activation. {yields} S1P stimulates fibroblast migration independently from SUR2/Kir6.1 channel. -- Abstract: The aim of this study was to characterize the effects of sphingosine-1-phosphate (S1P) on cardiac ventricular fibroblasts. Impacts of S1P on fibroblast excitability, cell migration, proliferation and secretion were characterized. The patch-clamp technique in the whole-cell configuration was used to study the S1P-induced current from mouse ventricular fibroblasts. The expression level of the S1P receptor during cell culture duration was evaluated by western-blot. Fibroblast proliferation and migration were quantified using the methylene blue assay and the Boyden chamber technique, respectively. Finally, fibroblast secretion properties were estimated by quantification of the IL-6 and collagen levels using ELISA and SIRCOL collagen assays, respectively. We found that S1P activated SUR2/Kir6.1 channel and that this effect was sensitive to specific inhibition of the S1P receptor of type 3 (S1P3R). In contrast, S1P1R receptor inhibition had no effect. Moreover, the S1P-induced current increased with cell culture duration whereas S1P3R expression level remained constant. The activation of SUR2/Kir6.1 channel by S1P via S1P3R stimulated cell proliferation and decreased IL-6 and collagen secretions. S1P also stimulated fibroblast migration via S1P3R but independently from SUR2/Kir6.1 channel activation. This study demonstrates that S1P, via S1P3R, affects cardiac ventricular fibroblasts function independently or through activation of SUR2/Kir6.1 channel. The latter effect occurs after fibroblasts differentiate into myofibroblasts, opening a new potential therapeutic strategy to modulate fibrosis after cardiac

  5. Advance in the Study of the Mechanisms Regulated by Sphingosine-1-Phosphate

    Ye, Fei; Kong, Xiangqian; Luo, Cheng

    2010-09-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid messenger in the cells that regulate gene expression and NF-KB signal pathway through unknown mechanisms. Recently, Cheng Luo, associate professor of DDDC in Shanghai Institute of Materia Medica, whose project was funded by the National Natural Science Foundation of China, joined in a research team led by Professor Sarah Spiegel of Virginia Commonwealth University. The team continuously made significant breakthroughs in understanding the regulation mechanism of Sphingosine-1-Phosphate. In September 2009, in a paper published on SCIENCE magazine (Science 2009, 325: 1254-7), they firstly demonstrated that S1P is a physiologically important regulator of histone deacetylases (HDACs), HDACs are direct intracellular targets of S1P. Furthermore, they identified the mechanism that S1P regulates gene expression through regulating the activity of HDACs. In June 24th, 2010, in another paper to be published on NATURE magazine (Nature 2010, June 24th, advance online publication) which reports the regulation of NF-KB signaling pathway by S1P. They demonstrate that S1P is the missing cofactor for TRAF2 (tumour-necrosis factor receptor-associated factor 2) and indicate a new paradigm for the regulation of lysine-63-linked poly-ubiquitination. The study also highlight the key role of SphK1 and its product S1P in TNF-α signalling and the canonical NF-KB activation pathway, and then play crucial role in inflammatory, antiapoptotic and immune processes. The identification of new mechanisms by which S1P regulates gene expression and TNF and NF-KB signaling pathway will light up the road to develop novel inhibitors that might be useful for treatment of cancer and inflammatory diseases.

  6. Sphingosine Kinase 1 and Sphingosine-1-Phosphate Signaling in Colorectal Cancer

    Yonghua Bao

    2017-10-01

    Full Text Available Sphingosine kinase 1 (Sphk1 is a highly conserved lipid kinase that phosphorylates sphingosine to form sphingosine-1-phosphate (S1P. Growing studies have demonstrated that Sphk1 is overexpressed in various types of solid cancers and can be induced by growth factors, cytokines, and carcinogens, leading to the increase of S1P production. Subsequently, the increased Sphk1/S1P facilitates cancer cell proliferation, mobility, angiogenesis, invasion, and metastasis. Therefore, Sphk1/S1P signaling plays oncogenic roles. This review summarizes the features of Sphk1/S1P signaling and their functions in colorectal cancer cell growth, tumorigenesis, and metastasis, as well as the possible underlying mechanisms.

  7. Apolipoprotein M mediates sphingosine-1-phosphate efflux from erythrocytes

    Christensen, Pernille M.; Bosteen, Markus H.; Hajny, Stefan

    2017-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid implicated in e.g. angiogenesis, lymphocyte trafficking, and endothelial barrier function. Erythrocytes are a main source of plasma S1P together with platelets and endothelial cells. Apolipoprotein M (apoM) in HDL carries 70% of plasma S1P, whereas...... 30% is carried by albumin. The current aim was to investigate the role of apoM in export of S1P from human erythrocytes. Erythrocytes exported S1P more efficiently to HDL than to albumin, particularly when apoM was present in HDL. In contrast, export of sphingosine to HDL was unaffected...... by the presence of apoM. The specific ability of apoM to promote export of S1P was independent of apoM being bound in HDL particles. Treatment with MK-571, an inhibitor of the ABCC1 transporter, effectively reduced export of S1P from human erythrocytes to apoM, whereas the export was unaffected by inhibitors...

  8. Reduction in serum sphingosine 1-phosphate concentration in malaria.

    Chuchard Punsawad

    Full Text Available Sphingosine 1-phosphate (S1P is a lipid mediator formed by the metabolism of sphingomyelin which is involved in the endothelial permeability and inflammation. Although the plasma S1P concentration is reportedly decreased in patients with cerebral malaria, the role of S1P in malaria is still unclear. The purpose of this study was to examine the impact of malaria on circulating S1P concentration and its relationship with clinical data in malaria patients. Serum S1P levels were measured in 29 patients with P. vivax, 30 patients with uncomplicated P. falciparum, and 13 patients with complicated P. falciparum malaria on admission and on day 7, compared with healthy subjects (n = 18 as control group. The lowest level of serum S1P concentration was found in the complicated P. falciparum malaria group, compared with P. vivax, uncomplicated P. falciparum patients and healthy controls (all p < 0.001. In addition, serum S1P level was positively correlated with platelet count, hemoglobin and hematocrit levels in malaria patients. In conclusions, low levels of S1P are associated with the severity of malaria, and are correlated with thrombocytopenia and anemia. These findings highlight a role of S1P in the severity of malaria and support the use of S1P and its analogue as a novel adjuvant therapy for malaria complications.

  9. Vascular and Immunobiology of the Circulatory Sphingosine 1-Phosphate Gradient

    Yanagida, Keisuke; Hla, Timothy

    2017-01-01

    Vertebrates are endowed with a closed circulatory system, the evolution of which required novel structural and regulatory changes. Furthermore, immune cell trafficking paradigms adapted to the barriers imposed by the closed circulatory system. How did such changes occur mechanistically? We propose that spatial compartmentalization of the lipid mediator sphingosine 1-phosphate (S1P) may be one such mechanism. In vertebrates, S1P is spatially compartmentalized in the blood and lymphatic circulation, thus comprising a sharp S1P gradient across the endothelial barrier. Circulatory S1P has critical roles in maturation and homeostasis of the vascular system as well as in immune cell trafficking. Physiological functions of S1P are tightly linked to shear stress, the key biophysical stimulus from blood flow. Thus, circulatory S1P confinement could be a primordial strategy of vertebrates in the development of a closed circulatory system. This review discusses the cellular and molecular basis of the S1P gradients and aims to interpret its physiological significance as a key feature of the closed circulatory system. PMID:27813829

  10. Aspirin Inhibits Platelet-Derived Sphingosine-1-Phosphate Induced Endothelial Cell Migration.

    Polzin, Amin; Knoop, Betül; Böhm, Andreas; Dannenberg, Lisa; Zurek, Mark; Zeus, Tobias; Kelm, Malte; Levkau, Bodo; Rauch, Bernhard H

    2018-01-01

    Aspirin plays a crucial role in the prevention of cardiovascular diseases. We previously described that aspirin has effects beyond inhibition of platelet aggregation, as it inhibited thrombin-mediated release of sphingosine-1-phosphate (S1P) from human platelets. S1P is a bioactive lipid with important functions on inflammation and apoptosis. In endothelial cells (EC), S1P is a key regulator of cell migration. In this study, we aimed to analyze the effects of aspirin on platelet-induced EC migration. Human umbilical EC migration was measured by Boyden chamber assay. EC migration was induced by platelet supernatants of thrombin receptor-activating peptide-1 (AP1) stimulated platelets. To investigate the S1P receptor subtype that promotes EC migration, specific inhibitors of S1P receptor subtypes were applied. S1P induced EC migration in a concentration-dependent manner. EC migration induced by AP1-stimulated platelet supernatants was reduced by aspirin. S1P1 receptor inhibition almost completely abolished EC migration induced by activated platelets. The inhibition of S1P2 or S1P3 receptor had no effect. Aspirin inhibits EC migration induced by activated platelets that is in part due to S1P and mediated by the endothelial S1P1 receptor. The clinical significance of this novel mechanism of aspirin action has to be investigated in future studies. © 2017 S. Karger AG, Basel.

  11. Insulin protects apoptotic cardiomyocytes from hypoxia/reoxygenation injury through the sphingosine kinase/sphingosine 1-phosphate axis.

    Huan Yu

    Full Text Available OBJECTIVE: Experimental and clinical studies have shown that administration of insulin during reperfusion is cardioprotective, but the mechanisms underlying this effect are still unknown. In this study, the ability of insulin to protect apoptotic cardiomyocytes from hypoxia/reoxygenation injury using the sphingosine kinase/sphingosine 1-phosphate axis was investigated. METHODS AND RESULTS: Rat cardiomyocytes were isolated and subjected to hypoxia and reoxygenation. [γ-32P] ATP was used to assess sphingosine kinase activity. Insulin was found to increase sphingosine kinase activity. Immunocytochemistry and Western blot analysis showed changes in the subcellular location of sphingosine kinase 1 from cytosol to the membrane in cardiomyocytes. Insulin caused cardiomyocytes to accumulate of S1P in a dose-dependent manner. FRET efficiency showed that insulin also transactivates the S1P1 receptor. TUNEL staining showed that administration of insulin during reoxygenation could to reduce the rate of reoxygenation-induced apoptosis, which is a requirement for SphK 1 activity. It also reduced the rate of activation of the S1P receptor and inhibited hypoxia/reoxygenation-induced cell death in cardiomyocytes. CONCLUSION: The sphingosine kinase 1/sphingosine 1-phosphate/S1P receptor axis is one pathway through which insulin protects rat cardiomyocytes from apoptosis induced by hypoxia/reoxygenation injury.

  12. Sphingosine 1-phosphate (S1P) signalling: Role in bone biology and potential therapeutic target for bone repair.

    Sartawi, Ziad; Schipani, Ernestina; Ryan, Katie B; Waeber, Christian

    2017-11-01

    The lipid mediator sphingosine 1-phosphate (S1P) affects cellular functions in most systems. Interest in its therapeutic potential has increased following the discovery of its G protein-coupled receptors and the recent availability of agents that can be safely administered in humans. Although the role of S1P in bone biology has been the focus of much less research than its role in the nervous, cardiovascular and immune systems, it is becoming clear that this lipid influences many of the functions, pathways and cell types that play a key role in bone maintenance and repair. Indeed, S1P is implicated in many osteogenesis-related processes including stem cell recruitment and subsequent differentiation, differentiation and survival of osteoblasts, and coupling of the latter cell type with osteoclasts. In addition, S1P's role in promoting angiogenesis is well-established. The pleiotropic effects of S1P on bone and blood vessels have significant potential therapeutic implications, as current therapeutic approaches for critical bone defects show significant limitations. Because of the complex effects of S1P on bone, the pharmacology of S1P-like agents and their physico-chemical properties, it is likely that therapeutic delivery of S1P agents will offer significant advantages compared to larger molecular weight factors. Hence, it is important to explore novel methods of utilizing S1P agents therapeutically, and improve our understanding of how S1P and its receptors modulate bone physiology and repair. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Role of sphingolipids in murine radiation-induced lung injury: protection by sphingosine 1-phosphate analogs

    Mathew, Biji; Jacobson, Jeffrey R.; Berdyshev, Evgeny; Huang, Yong; Sun, Xiaoguang; Zhao, Yutong; Gerhold, Lynnette M.; Siegler, Jessica; Evenoski, Carrie; Wang, Ting; Zhou, Tong; Zaidi, Rafe; Moreno-Vinasco, Liliana; Bittman, Robert; Chen, Chin Tu; LaRiviere, Patrick J.; Sammani, Saad; Lussier, Yves A.; Dudek, Steven M.; Natarajan, Viswanathan; Weichselbaum, Ralph R.; Garcia, Joe G. N.

    2011-01-01

    Clinically significant radiation-induced lung injury (RILI) is a common toxicity in patients administered thoracic radiotherapy. Although the molecular etiology is poorly understood, we previously characterized a murine model of RILI in which alterations in lung barrier integrity surfaced as a potentially important pathobiological event and genome-wide lung gene mRNA levels identified dysregulation of sphingolipid metabolic pathway genes. We hypothesized that sphingolipid signaling components serve as modulators and novel therapeutic targets of RILI. Sphingolipid involvement in murine RILI was confirmed by radiation-induced increases in lung expression of sphingosine kinase (SphK) isoforms 1 and 2 and increases in the ratio of ceramide to sphingosine 1-phosphate (S1P) and dihydro-S1P (DHS1P) levels in plasma, bronchoalveolar lavage fluid, and lung tissue. Mice with a targeted deletion of SphK1 (SphK1−/−) or with reduced expression of S1P receptors (S1PR1+/−, S1PR2−/−, and S1PR3−/−) exhibited marked RILI susceptibility. Finally, studies of 3 potent vascular barrier-protective S1P analogs, FTY720, (S)-FTY720-phosphonate (fTyS), and SEW-2871, identified significant RILI attenuation and radiation-induced gene dysregulation by the phosphonate analog, fTyS (0.1 and 1 mg/kg i.p., 2×/wk) and to a lesser degree by SEW-2871 (1 mg/kg i.p., 2×/wk), compared with those in controls. These results support the targeting of S1P signaling as a novel therapeutic strategy in RILI.—Mathew, B., Jacobson, J. R., Berdyshev, E., Huang, Y., Sun, X., Zhao, Y., Gerhold, L. M., Siegler, J., Evenoski, C., Wang, T., Zhou, T., Zaidi, R., Moreno-Vinasco, L., Bittman, R., Chen, C. T., LaRiviere, P. J., Sammani, S., Lussier, Y. A., Dudek, S. M., Natarajan, V., Weichselbaum, R. R., Garcia, J. G. N. Role of sphingolipids in murine radiation-induced lung injury: protection by sphingosine 1-phosphate analogs. PMID:21712494

  14. Sphingosine-1-Phosphate Signaling in Immune Cells and Inflammation: Roles and Therapeutic Potential

    Masayo Aoki

    2016-01-01

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive sphingolipid metabolite involved in many critical cell processes. It is produced by the phosphorylation of sphingosine by sphingosine kinases (SphKs and exported out of cells via transporters such as spinster homolog 2 (Spns2. S1P regulates diverse physiological processes by binding to specific G protein-binding receptors, S1P receptors (S1PRs 1–5, through a process coined as “inside-out signaling.” The S1P concentration gradient between various tissues promotes S1PR1-dependent migration of T cells from secondary lymphoid organs into the lymphatic and blood circulation. S1P suppresses T cell egress from and promotes retention in inflamed peripheral tissues. S1PR1 in T and B cells as well as Spns2 in endothelial cells contributes to lymphocyte trafficking. FTY720 (Fingolimod is a functional antagonist of S1PRs that induces systemic lymphopenia by suppression of lymphocyte egress from lymphoid organs. In this review, we summarize previous findings and new discoveries about the importance of S1P and S1PR signaling in the recruitment of immune cells and lymphocyte retention in inflamed tissues. We also discuss the role of S1P-S1PR1 axis in inflammatory diseases and wound healing.

  15. Endothelium-protective sphingosine-1-phosphate provided by HDL-associated apolipoprotein M

    Christoffersen, Christina; Obinata, Hideru; Kumaraswamy, Sunil B

    2011-01-01

    Protection of the endothelium is provided by circulating sphingosine-1-phosphate (S1P), which maintains vascular integrity. We show that HDL-associated S1P is bound specifically to both human and murine apolipoprotein M (apoM). Thus, isolated human ApoM(+) HDL contained S1P, whereas ApoM(-) HDL did...... not. Moreover, HDL in Apom(-/-) mice contains no S1P, whereas HDL in transgenic mice overexpressing human apoM has an increased S1P content. The 1.7-Å structure of the S1P-human apoM complex reveals that S1P interacts specifically with an amphiphilic pocket in the lipocalin fold of apoM. Human ApoM......(+) HDL induced S1P(1) receptor internalization, downstream MAPK and Akt activation, endothelial cell migration, and formation of endothelial adherens junctions, whereas apoM(-) HDL did not. Importantly, lack of S1P in the HDL fraction of Apom(-/-) mice decreased basal endothelial barrier function in lung...

  16. Sphingosine-1-Phosphate Signaling Regulates Myogenic Responsiveness in Human Resistance Arteries.

    Sonya Hui

    Full Text Available We recently identified sphingosine-1-phosphate (S1P signaling and the cystic fibrosis transmembrane conductance regulator (CFTR as prominent regulators of myogenic responsiveness in rodent resistance arteries. However, since rodent models frequently exhibit limitations with respect to human applicability, translation is necessary to validate the relevance of this signaling network for clinical application. We therefore investigated the significance of these regulatory elements in human mesenteric and skeletal muscle resistance arteries. Mesenteric and skeletal muscle resistance arteries were isolated from patient tissue specimens collected during colonic or cardiac bypass surgery. Pressure myography assessments confirmed endothelial integrity, as well as stable phenylephrine and myogenic responses. Both human mesenteric and skeletal muscle resistance arteries (i express critical S1P signaling elements, (ii constrict in response to S1P and (iii lose myogenic responsiveness following S1P receptor antagonism (JTE013. However, while human mesenteric arteries express CFTR, human skeletal muscle resistance arteries do not express detectable levels of CFTR protein. Consequently, modulating CFTR activity enhances myogenic responsiveness only in human mesenteric resistance arteries. We conclude that human mesenteric and skeletal muscle resistance arteries are a reliable and consistent model for translational studies. We demonstrate that the core elements of an S1P-dependent signaling network translate to human mesenteric resistance arteries. Clear species and vascular bed variations are evident, reinforcing the critical need for further translational study.

  17. Sphingosine 1-Phosphate as a Link between Blood Coagulation and Inflammation

    Bernhard Hermann Rauch

    2014-06-01

    Full Text Available Sphingosine 1-phosphate (S1P is a multifunctional signaling lipid generated from sphingosine by sphingosine kinases. S1P formation has been shown in numerous cells in the circulation, including platelets, vascular endothelial and smooth muscle cells and monocytes. S1P also exerts multiple effects on these cells, i.e. cell proliferation and migration, activation of proinflammatory signaling pathways and release of additional inflammatory mediators. Similar activities and targets have also been identified for activated clotting factors such as thrombin or the activated factor-X (FXa, suggesting a possible involvement of S1P in thrombus-associated cellular signaling and thrombin-induced inflammatory reactions. Several levels of S1P-mediated, thrombin /FXa-induced signaling have already been identified: regulation of sphingosine kinase expression and activity, stimulation of S1P release from platelets and other cells and, possibly regulation of S1P-receptors on target cells. This review summarizes the current state of knowledge about S1P as a clotting factor-regulated molecular link between blood coagulation and inflammation. It is concluded that S1P might represent an until now underestimated lipid mediator of inflammatory reactions following activation of the clotting system and, in this context, also involved in the development and progression of atherosclerosis.

  18. Sustained release of sphingosine 1-phosphate for therapeutic arteriogenesis and bone tissue engineering.

    Sefcik, Lauren S; Petrie Aronin, Caren E; Wieghaus, Kristen A; Botchwey, Edward A

    2008-07-01

    Sphingosine 1-phosphate (S1P) is a bioactive phospholipid that impacts migration, proliferation, and survival in diverse cell types, including endothelial cells, smooth muscle cells, and osteoblast-like cells. In this study, we investigated the effects of sustained release of S1P on microvascular remodeling and associated bone defect healing in vivo. The murine dorsal skinfold window chamber model was used to evaluate the structural remodeling response of the microvasculature. Our results demonstrated that 1:400 (w/w) loading and subsequent sustained release of S1P from poly(lactic-co-glycolic acid) (PLAGA) significantly enhanced lumenal diameter expansion of arterioles and venules after 3 and 7 days. Incorporation of 5-bromo-2-deoxyuridine (BrdU) at day 7 revealed significant increases in mural cell proliferation in response to S1P delivery. Additionally, three-dimensional (3D) scaffolds loaded with S1P (1:400) were implanted into critical-size rat calvarial defects, and healing of bony defects was assessed by radiograph X-ray, microcomputed tomography (muCT), and histology. Sustained release of S1P significantly increased the formation of new bone after 2 and 6 weeks of healing and histological results suggest increased numbers of blood vessels in the defect site. Taken together, these experiments support the use of S1P delivery for promoting microvessel diameter expansion and improving the healing outcomes of tissue-engineered therapies.

  19. Paradoxical Association of Postoperative Plasma Sphingosine-1-Phosphate with Breast Cancer Aggressiveness and Chemotherapy

    Rajesh Ramanathan

    2017-01-01

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive lipid mediator that has been shown to serve an important regulatory function in breast cancer progression. This study analyzes plasma S1P levels in breast cancer patients undergoing adjuvant therapy as compared to healthy control volunteers. 452 plasma S1P samples among 158 breast cancer patients, along with 20 healthy control volunteers, were analyzed. Mean S1P levels did not significantly differ between cancer patients and controls. Smoking was associated with higher S1P levels in cancer patients. Baseline S1P levels had weak inverse correlation with levels of the inflammatory mediator interleukin- (IL- 17 and CCL-2 and positive correlation with tumor necrosis factor alpha (TNF-α. Midpoint S1P levels during adjuvant therapy were lower than baseline, with near return to baseline after completion, indicating a relationship between chemotherapy and circulating S1P. While stage of disease did not correlate with plasma S1P levels, they were lower among patients with Her2-enriched and triple-negative breast cancer as compared to luminal-type breast cancer. Plasma S1P levels are paradoxically suppressed in aggressive breast cancer and during adjuvant chemotherapy, which raises the possibility that postoperative plasma S1P levels do not reflect S1P secretion from resected breast cancer.

  20. Indomethacin differentiates the renal effects of sphingosine-1-phosphate and sphingosylphosphorylcholine

    Czyborra, Claudia; Bischoff, Angela; Michel, Martin C.

    2006-01-01

    The sphingomyelin breakdown products sphingosine-1-phosphate (S1P) and sphingosylphosphorylcholine (SPC) constrict intrarenal microvessels in vitro in a pertussis toxin (PTX) sensitive manner, and S1P also reduces renal blood flow in vivo. Nevertheless, both S1P and SPC have been reported to enhance

  1. Activated platelets release sphingosine 1-phosphate and induce hypersensitivity to noxious heat stimuli in vivo

    Daniela eWeth

    2015-04-01

    Full Text Available At the site of injury activated platelets release various mediators, one of which is sphingosine 1-phosphate (S1P. It was the aim of this study to explore whether activated human platelets had a pronociceptive effect in an in vivo mouse model and whether this effect was based on the release of S1P and subsequent activation of neuronal S1P receptors 1 or 3. Human platelets were prepared in different concentrations (105/µl, 106/µl, 107/µl and assessed in mice with different genetic backgrounds (WT, S1P1fl/fl, SNS-S1P1-/-, S1P3-/-. Intracutaneous injections of activated human platelets induced a significant, dose-dependent hypersensitivity to noxious thermal stimulation. The degree of heat hypersensitivity correlated with the platelet concentration as well as the platelet S1P content and the amount of S1P released upon platelet activation as measured with LC MS/MS. Despite the significant correlations between S1P and platelet count, no difference in paw withdrawal latency (PWL was observed in mice with a global null mutation of the S1P3 receptor or a conditional deletion of the S1P1 receptor in nociceptive primary afferents. Furthermore, neutralisation of S1P with a selective anti-S1P antibody did not abolish platelet induced heat hypersensitivity. Our results suggest that activated platelets release S1P and induce heat hypersensitivity in vivo. However, the platelet induced heat hypersensitivity was caused by mediators other than S1P.

  2. Molecular mechanism of sphingosine-1-phosphate action in Duchenne muscular dystrophy

    Diem-Hang Nguyen-Tran

    2014-01-01

    Full Text Available Duchenne muscular dystrophy (DMD is a lethal muscle-wasting disease. Studies in Drosophila showed that genetic increase of the levels of the bioactive sphingolipid sphingosine-1-phosphate (S1P or delivery of 2-acetyl-5-tetrahydroxybutyl imidazole (THI, an S1P lyase inhibitor, suppresses dystrophic muscle degeneration. In the dystrophic mouse (mdx, upregulation of S1P by THI increases regeneration and muscle force. S1P can act as a ligand for S1P receptors and as a histone deacetylase (HDAC inhibitor. Because Drosophila has no identified S1P receptors and DMD correlates with increased HDAC2 levels, we tested whether S1P action in muscle involves HDAC inhibition. Here we show that beneficial effects of THI treatment in mdx mice correlate with significantly increased nuclear S1P, decreased HDAC activity and increased acetylation of specific histone residues. Importantly, the HDAC2 target microRNA genes miR-29 and miR-1 are significantly upregulated, correlating with the downregulation of the miR-29 target Col1a1 in the diaphragm of THI-treated mdx mice. Further gene expression analysis revealed a significant THI-dependent decrease in inflammatory genes and increase in metabolic genes. Accordingly, S1P levels and functional mitochondrial activity are increased after THI treatment of differentiating C2C12 cells. S1P increases the capacity of the muscle cell to use fatty acids as an energy source, suggesting that THI treatment could be beneficial for the maintenance of energy metabolism in mdx muscles.

  3. Sphingosine 1-phosphate mediates hyperalgesia via a neutrophil-dependent mechanism.

    Amanda Finley

    Full Text Available Novel classes of pain-relieving molecules are needed to fill the void between non-steroidal anti-inflammatory agents and narcotics. We have recently shown that intraplantar administration of sphingosine 1-phosphate (S1P in rats causes peripheral sensitization and hyperalgesia through the S1P(1 receptor subtype (S1PR(1: the mechanism(s involved are largely unknown and were thus explored in the present study. Intraplantar injection of carrageenan in rats led to a time-dependent development of thermal hyperalgesia that was associated with pronounced edema and infiltration of neutrophils in paw tissues. Inhibition of 1 S1P formation with SK-I, a sphingosine kinase inhibitor, 2 S1P bioavailability with the S1P blocking antibody Sphingomab, LT1002 (but not its negative control, LT1017 or 3 S1P actions through S1PR(1 with the selective S1PR(1 antagonist, W146 (but not its inactive enantiomer, W140 blocked thermal hyperalgesia and infiltration of neutrophils. Taken together, these findings identify S1P as an important contributor to inflammatory pain acting through S1PR(1 to elicit hyperalgesia in a neutrophil-dependant manner. In addition and in further support, we demonstrate that the development of thermal hyperalgesia following intraplantar injection of S1P or SEW2871 (an S1PR(1 agonist was also associated with neutrophilic infiltration in paw tissues as these events were attenuated by fucoidan, an inhibitor of neutrophilic infiltration. Importantly, FTY720, an FDA-approved S1P receptor modulator known to block S1P-S1PR(1 signaling, attenuated carrageenan-induced thermal hyperalgesia and associated neutrophil infiltration. Targeting the S1P/S1PR(1 axis opens a therapeutic strategy for the development of novel non-narcotic anti-hyperalgesic agents.

  4. Chemical Hypoxia Brings to Light Altered Autocrine Sphingosine-1-Phosphate Signalling in Rheumatoid Arthritis Synovial Fibroblasts

    Chenqi Zhao

    2015-01-01

    Full Text Available Emerging evidence suggests a role for sphingosine-1-phosphate (S1P in various aspects of rheumatoid arthritis (RA pathogenesis. In this study we compared the effect of chemical hypoxia induced by cobalt chloride (CoCl2 on the expression of S1P metabolic enzymes and cytokine/chemokine secretion in normal fibroblast-like synoviocytes (FLS and RAFLS. RAFLS incubated with CoCl2, but not S1P, produced less IL-8 and MCP-1 than normal FLS. Furthermore, incubation with the S1P2 and S1P3 receptor antagonists, JTE-013 and CAY10444, reduced CoCl2-mediated chemokine production in normal FLS but not in RAFLS. RAFLS showed lower levels of intracellular S1P and enhanced mRNA expression of S1P phosphatase 1 (SGPP1 and S1P lyase (SPL, the enzymes that are involved in intracellular S1P degradation, when compared to normal FLS. Incubation with CoCl2 decreased SGPP1 mRNA and protein and SPL mRNA as well. Inhibition of SPL enhanced CoCl2-mediated cytokine/chemokine release and restored autocrine activation of S1P2 and S1P3 receptors in RAFLS. The results suggest that the sphingolipid pathway regulating the intracellular levels of S1P is dysregulated in RAFLS and has a significant impact on cell autocrine activation by S1P. Altered sphingolipid metabolism in FLS from patients with advanced RA raises the issue of synovial cell burnout due to chronic inflammation.

  5. Vehicle-dependent Effects of Sphingosine 1-phosphate on Plasminogen Activator Inhibitor-1 Expression

    Takahashi, Chiharu; Kurano, Makoto; Nishikawa, Masako; Kano, Kuniyuki; Dohi, Tomotaka; Miyauchi, Katsumi; Daida, Hiroyuki; Shimizu, Tomo; Aoki, Junken

    2017-01-01

    Aim: Sphingosine 1-phosphate (S1P) has been suggested to be a positive regulator of plasminogen activator inhibitor 1 (PAI-1) in adipocytes, while some studies are not consistent with this prothrombotic property of S1P. Since S1P is bound to apolipoprotein M (apoM) on HDL or to albumin in plasma, we compared the properties of these two forms on the PAI-1 induction. Methods: We investigated the associations of S1P, apoM, and PAI-1 concentrations in the plasma of normal coronary artery (NCA), stable angina pectoris (SAP), and acute coronary syndrome (ACS) subjects (n = 32, 71, and 38, respectively). Then, we compared the effects of S1P with various vehicles on the PAI-1 expression in 3T3L1 adipocytes. We also investigated the modulation of the PAI-1 levels in mice infected with adenovirus coding apoM. Results: Among ACS subjects, the PAI-1 level was positively correlated with the S1P level, but not the apoM level. In adipocytes, S1P bound to an apoM-rich vehicle induced PAI-1 expression to a lesser extent than the control vehicle, while S1P bound to an apoM-depleted vehicle induced PAI-1 expression to a greater extent than the control vehicle in 3T3L1 adipocytes. Additionally, apoM overexpression in mice failed to modulate the plasma PAI-1 level and the adipose PAI-1 expression level. S1P bound to albumin increased PAI-1 expression through the S1P receptor 2-Rho/ROCK-NFκB pathway. Conclusion: S1P bound to albumin, but not to apoM, induces PAI-1 expression in adipocytes, indicating that S1P can exert different properties on the pathogenesis of vascular diseases, depending on its vehicle. PMID:28321011

  6. The Role of Sphingosine-1-Phosphate and Ceramide-1-Phosphate in Inflammation and Cancer

    Nitai C. Hait

    2017-01-01

    Full Text Available Inflammation is part of our body’s response to tissue injury and pathogens. It helps to recruit various immune cells to the site of inflammation and activates the production of mediators to mobilize systemic protective processes. However, chronic inflammation can increase the risk of diseases like cancer. Apart from cytokines and chemokines, lipid mediators, particularly sphingosine-1-phosphate (S1P and ceramide-1-phosphate (C1P, contribute to inflammation and cancer. S1P is an important player in inflammation-associated colon cancer progression. On the other hand, C1P has been recognized to be involved in cancer cell growth, migration, survival, and inflammation. However, whether C1P is involved in inflammation-associated cancer is not yet established. In contrast, few studies have also suggested that S1P and C1P are involved in anti-inflammatory pathways regulated in certain cell types. Ceramide is the substrate for ceramide kinase (CERK to yield C1P, and sphingosine is phosphorylated to S1P by sphingosine kinases (SphKs. Biological functions of sphingolipid metabolites have been studied extensively. Ceramide is associated with cell growth inhibition and enhancement of apoptosis while S1P and C1P are associated with enhancement of cell growth and survival. Altogether, S1P and C1P are important regulators of ceramide level and cell fate. This review focuses on S1P and C1P involvement in inflammation and cancer with emphasis on recent progress in the field.

  7. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

    Nagata, Yosuke, E-mail: cynagata@mail.ecc.u-tokyo.ac.jp; Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-08-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

  8. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

    Nagata, Yosuke; Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-01-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

  9. Pseudomonas-derived ceramidase induces production of inflammatory mediators from human keratinocytes via sphingosine-1-phosphate.

    Ami Oizumi

    Full Text Available Ceramide is important for water retention and permeability barrier functions in the stratum corneum, and plays a key role in the pathogenesis of atopic dermatitis (AD. A Pseudomonas aeruginosa-derived neutral ceramidase (PaCDase isolated from a patient with AD was shown to effectively degrade ceramide in the presence of Staphylococcus aureus-derived lipids or neutral detergents. However, the effect of ceramide metabolites on the functions of differentiating keratinocytes is poorly understood. We found that the ceramide metabolite sphingosine-1-phosphate (S1P stimulated the production of inflammatory mediators such as TNF-α and IL-8 from three-dimensionally cultured human primary keratinocytes (termed "3D keratinocytes", which form a stratum corneum. PaCDase alone did not affect TNF-α gene expression in 3D keratinocytes. In the presence of the detergent Triton X-100, which damages stratum corneum structure, PaCDase, but not heat-inactivated PaCDase or PaCDase-inactive mutant, induced the production of TNF-α, endothelin-1, and IL-8, indicating that this production was dependent on ceramidase activity. Among various ceramide metabolites, sphingosine and S1P enhanced the gene expression of TNF-α, endothelin-1, and IL-8. The PaCDase-enhanced expression of these genes was inhibited by a sphingosine kinase inhibitor and by an S1P receptor antagonist VPC 23019. The TNF-α-binding antibody infliximab suppressed the PaCDase-induced upregulation of IL-8, but not TNF-α, mRNA. PaCDase induced NF-κB p65 phosphorylation. The NF-κB inhibitor curcumin significantly inhibited PaCDase-induced expression of IL-8 and endothelin-1. VPC 23019 and infliximab inhibited PaCDase-induced NF-κB p65 phosphorylation and reduction in the protein level of the NF-κB inhibitor IκBα. Collectively, these findings suggest that (i 3D keratinocytes produce S1P from sphingosine, which is produced through the hydrolysis of ceramide by PaCDase, (ii S1P induces the production

  10. Sphingosine 1-Phosphate (S1P) Carrier-dependent Regulation of Endothelial Barrier

    Wilkerson, Brent A.; Grass, G. Daniel; Wing, Shane B.; Argraves, W. Scott; Argraves, Kelley M.

    2012-01-01

    Sphingosine 1-phosphate (S1P) is a blood-borne lysosphingolipid that acts to promote endothelial cell (EC) barrier function. In plasma, S1P is associated with both high density lipoproteins (HDL) and albumin, but it is not known whether the carriers impart different effects on S1P signaling. Here we establish that HDL-S1P sustains EC barrier longer than albumin-S1P. We showed that the sustained barrier effects of HDL-S1P are dependent on signaling by the S1P receptor, S1P1, and involve persistent activation of Akt and endothelial NOS (eNOS), as well as activity of the downstream NO target, soluble guanylate cyclase (sGC). Total S1P1 protein levels were found to be higher in response to HDL-S1P treatment as compared with albumin-S1P, and this effect was not associated with increased S1P1 mRNA or dependent on de novo protein synthesis. Several pieces of evidence indicate that long term EC barrier enhancement activity of HDL-S1P is due to specific effects on S1P1 trafficking. First, the rate of S1P1 degradation, which is proteasome-mediated, was slower in HDL-S1P-treated cells as compared with cells treated with albumin-S1P. Second, the long term barrier-promoting effects of HDL-S1P were abrogated by treatment with the recycling blocker, monensin. Finally, cell surface levels of S1P1 and levels of S1P1 in caveolin-enriched microdomains were higher after treatment with HDL-S1P as compared with albumin-S1P. Together, the findings reveal S1P carrier-specific effects on S1P1 and point to HDL as the physiological mediator of sustained S1P1-PI3K-Akt-eNOS-sGC-dependent EC barrier function. PMID:23135269

  11. Smad3 deficiency leads to mandibular condyle degradation via the sphingosine 1-phosphate (S1P)/S1P3 signaling axis.

    Mori, Hiroki; Izawa, Takashi; Tanaka, Eiji

    2015-10-01

    Temporomandibular joint osteoarthritis is a degenerative disease that is characterized by permanent cartilage destruction. Transforming growth factor (TGF)-β is one of the most abundant cytokines in the bone matrix and is shown to regulate the migration of osteoprogenitor cells. It is hypothesized that TGF-β/Smad3 signaling affects cartilage homeostasis by influencing sphingosine 1-phosphate (S1P)/S1P receptor signaling and chondrocyte migration. We therefore investigated the molecular mechanisms by which crosstalk may occur between TGF-β/Smad3 and S1P/S1P receptor signaling to maintain condylar cartilage and to prevent temporomandibular joint osteoarthritis. Abnormalities in the condylar subchondral bone, including dynamic changes in bone mineral density and microstructure, were observed in Smad3(-/-) mice by microcomputed tomography. Cell-free regions and proteoglycan loss characterized the cartilage degradation present, and increased numbers of apoptotic chondrocytes and matrix metalloproteinase 13(+) chondrocytes were also detected. Furthermore, expression of S1P receptor 3 (S1P3), but not S1P1 or S1P2, was significantly down-regulated in the condylar cartilage of Smad3(-/-) mice. By using RNA interference technology and pharmacologic tools, S1P was found to transactivate Smad3 in an S1P3/TGF-β type II receptor-dependent manner, and S1P3 was found to be required for TGF-β-induced migration of chondrocyte cells and downstream signal transduction via Rac1, RhoA, and Cdc42. Taken together, these results indicate that the Smad3/S1P3 signaling pathway plays an important role in the pathogenesis of temporomandibular joint osteoarthritis. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  12. Extracellular sphingosine-1-phosphate: a novel actor in human glioblastoma stem cell survival.

    Elena Riccitelli

    Full Text Available Glioblastomas are the most frequent and aggressive intracranial neoplasms in humans, and despite advances and the introduction of the alkylating agent temozolomide in therapy have improved patient survival, resistance mechanisms limit benefits. Recent studies support that glioblastoma stem-like cells (GSCs, a cell subpopulation within the tumour, are involved in the aberrant expansion and therapy resistance properties of glioblastomas, through still unclear mechanisms. Emerging evidence suggests that sphingosine-1-phosphate (S1P a potent onco-promoter able to act as extracellular signal, favours malignant and chemoresistance properties in GSCs. Notwithstanding, the origin of S1P in the GSC environment remains unknown. We investigated S1P metabolism, release, and role in cell survival properties of GSCs isolated from either U87-MG cell line or a primary culture of human glioblastoma. We show that both GSC models, grown as neurospheres and expressing GSC markers, are resistant to temozolomide, despite not expressing the DNA repair protein MGMT, a major contributor to temozolomide-resistance. Pulse experiments with labelled sphingosine revealed that both GSC types are able to rapidly phosphorylate the long-chain base, and that the newly produced S1P is efficiently degraded. Of relevance, we found that S1P was present in GSC extracellular medium, its level being significantly higher than in U87-MG cells, and that the extracellular/intracellular ratio of S1P was about ten-fold higher in GSCs. The activity of sphingosine kinases was undetectable in GSC media, suggesting that mechanisms of S1P transport to the extracellular environment are constitutive in GSCs. In addition we found that an inhibitor of S1P biosynthesis made GSCs sensitive to temozolomide (TMZ, and that exogenous S1P reverted this effect, thus involving extracellular S1P as a GSC survival signal in TMZ resistance. Altogether our data implicate for the first time GSCs as a pivotal source

  13. Sphingosine-1-Phosphate Lyase Deficient Cells as a Tool to Study Protein Lipid Interactions.

    Mathias J Gerl

    Full Text Available Cell membranes contain hundreds to thousands of individual lipid species that are of structural importance but also specifically interact with proteins. Due to their highly controlled synthesis and role in signaling events sphingolipids are an intensely studied class of lipids. In order to investigate their metabolism and to study proteins interacting with sphingolipids, metabolic labeling based on photoactivatable sphingoid bases is the most straightforward approach. In order to monitor protein-lipid-crosslink products, sphingosine derivatives containing a reporter moiety, such as a radiolabel or a clickable group, are used. In normal cells, degradation of sphingoid bases via action of the checkpoint enzyme sphingosine-1-phosphate lyase occurs at position C2-C3 of the sphingoid base and channels the resulting hexadecenal into the glycerolipid biosynthesis pathway. In case the functionalized sphingosine looses the reporter moiety during its degradation, specificity towards sphingolipid labeling is maintained. In case degradation of a sphingosine derivative does not remove either the photoactivatable or reporter group from the resulting hexadecenal, specificity towards sphingolipid labeling can be achieved by blocking sphingosine-1-phosphate lyase activity and thus preventing sphingosine derivatives to be channeled into the sphingolipid-to-glycerolipid metabolic pathway. Here we report an approach using clustered, regularly interspaced, short palindromic repeats (CRISPR-associated nuclease Cas9 to create a sphingosine-1-phosphate lyase (SGPL1 HeLa knockout cell line to disrupt the sphingolipid-to-glycerolipid metabolic pathway. We found that the lipid and protein compositions as well as sphingolipid metabolism of SGPL1 knock-out HeLa cells only show little adaptations, which validates these cells as model systems to study transient protein-sphingolipid interactions.

  14. Emerging Role of Sphingosine-1-phosphate in Inflammation, Cancer, and Lymphangiogenesis

    Kazuaki Takabe

    2013-07-01

    Full Text Available The main function of the lymphatic system is to control and maintain fluid homeostasis, lipid transport, and immune cell trafficking. In recent years, the pathological roles of lymphangiogenesis, the generation of new lymphatic vessels from preexisting ones, in inflammatory diseases and cancer progression are beginning to be elucidated. Sphingosine-1-phosphate (S1P, a bioactive lipid, mediates multiple cellular events, such as cell proliferation, differentiation, and trafficking, and is now known as an important mediator of inflammation and cancer. In this review, we will discuss recent findings showing the emerging role of S1P in lymphangiogenesis, in inflammation, and in cancer.

  15. Binding Characteristics of Sphingosine-1-Phosphate to ApoM hints to Assisted Release Mechanism via the ApoM Calyx-Opening

    Zhang, Hansi; Pluhackova, Kristyna; Jiang, Zhenyan; Böckmann, Rainer A.

    2016-08-01

    Sphingosine-1-phosphate (S1P) is a lysophospholipid mediator carried by the HDL-associated apoM protein in blood, regulating many physiological processes by activating the G protein-coupled S1P receptor in mammals. Despite the solved crystal structure of the apoM-S1P complex, the mechanism of S1P release from apoM as a part of the S1P pathway is unknown. Here, the dynamics of the wild type apoM-S1P complex as well as of mutants were investigated by means of atomistic molecular dynamics simulations. The potential of mean force for S1P unbinding from apoM reflected a large binding strength of more than 60 kJ/mol. This high unbinding free energy for S1P underlines the observed specificity of the physiological effects of S1P as it suggests that the spontaneous release of S1P from apoM is unlikely. Instead, S1P release and thus the control of this bioactive lipid probably requires the tight interaction with other molecules, e.g. with the S1P receptor. Mutations of specific S1P anchoring residues of apoM decreased the energetic barrier by up to 20 kJ/mol. Moreover, the ligand-free apoM protein is shown to adopt a more open upper hydrophilic binding pocket and to result in complete closure of the lower hydrophobic cavity, suggesting a mechanism for adjusting the gate for ligand access.

  16. Sphingosine-1-phosphate induces human endothelial VEGF and MMP-2 production via transcription factor ZNF580: Novel insights into angiogenesis

    Sun, Hui-Yan; Wei, Shu-Ping; Xu, Rui-Cheng; Xu, Peng-Xiao; Zhang, Wen-Cheng

    2010-01-01

    Sphingosine-1-phosphate (S1P)-induced migration and proliferation of endothelial cells are critical for angiogenesis. C2H2-zinc finger (ZNF) proteins usually play an essential role in altering gene expression and regulating the angiogenesis. The aim of this study is to investigate whether a novel human C2H2-zinc finger gene ZNF580 (Gene ID: 51157) is involved in the migration and proliferation of endothelial cells stimulated by S1P. Our study shows that EAhy926 endothelial cells express S1P1, S1P3 and S1P5 receptors. Furthermore, S1P upregulates both ZNF580 mRNA and protein levels in a concentration- and time-dependent manner. SB203580, the specific inhibitor of the p38 mitogen-activated protein kinase (p38 MAPK) pathway, blocks the S1P-induced upregulation of ZNF580. Moreover, overexpression/downexpression of ZNF580 in EAhy926 cells leads to the enhancement/decrease of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) expression as well as the migration and proliferation of EAhy926 endothelial cells. These results elucidate the important role that ZNF580 plays in the process of migration and proliferation of endothelial cells, which provides a foundation for a novel approach to regulate angiogenesis.

  17. Sphingosine-1-phosphate induces human endothelial VEGF and MMP-2 production via transcription factor ZNF580: Novel insights into angiogenesis

    Sun, Hui-Yan, E-mail: shy35309@sohu.com [Department of Physiology and Pathophysiology, Medical College of Chinese People' s Armed Police Forces, Tianjin 300162 (China); Wei, Shu-Ping, E-mail: weishuping_83@163.com [Department of Physiology and Pathophysiology, Medical College of Chinese People' s Armed Police Forces, Tianjin 300162 (China); Xu, Rui-Cheng, E-mail: xu_rc@sohu.com [Department of Physiology and Pathophysiology, Medical College of Chinese People' s Armed Police Forces, Tianjin 300162 (China); Xu, Peng-Xiao, E-mail: xupengxiao1228@sina.com [Department of Physiology and Pathophysiology, Medical College of Chinese People' s Armed Police Forces, Tianjin 300162 (China); Zhang, Wen-Cheng, E-mail: wenchengzhang@yahoo.com [Department of Physiology and Pathophysiology, Medical College of Chinese People' s Armed Police Forces, Tianjin 300162 (China)

    2010-05-07

    Sphingosine-1-phosphate (S1P)-induced migration and proliferation of endothelial cells are critical for angiogenesis. C2H2-zinc finger (ZNF) proteins usually play an essential role in altering gene expression and regulating the angiogenesis. The aim of this study is to investigate whether a novel human C2H2-zinc finger gene ZNF580 (Gene ID: 51157) is involved in the migration and proliferation of endothelial cells stimulated by S1P. Our study shows that EAhy926 endothelial cells express S1P1, S1P3 and S1P5 receptors. Furthermore, S1P upregulates both ZNF580 mRNA and protein levels in a concentration- and time-dependent manner. SB203580, the specific inhibitor of the p38 mitogen-activated protein kinase (p38 MAPK) pathway, blocks the S1P-induced upregulation of ZNF580. Moreover, overexpression/downexpression of ZNF580 in EAhy926 cells leads to the enhancement/decrease of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) expression as well as the migration and proliferation of EAhy926 endothelial cells. These results elucidate the important role that ZNF580 plays in the process of migration and proliferation of endothelial cells, which provides a foundation for a novel approach to regulate angiogenesis.

  18. Role of Sphingosine-1-Phosphate in Mast Cell Functions and Asthma and Its Regulation by Non-Coding RNA

    Rohit Saluja

    2017-05-01

    Full Text Available Sphingolipid metabolites are emerging as important signaling molecules in allergic diseases specifically asthma. One of the sphingolipid metabolite, sphingosine-1-phosphate (S1P, is involved in cell differentiation, proliferation, survival, migration, and angiogenesis. In the allergic diseases, alteration of S1P levels influences the differentiation and responsiveness of mast cells (MCs. S1P is synthesized by two sphingosine kinases (SphKs, sphingosine kinase 1, and sphingosine kinase 2. Engagement of IgE to the FcεRI receptor induces the activation of both the SphKs and generates S1P. Furthermore, SphKs are also essential to FcεRI-mediated MC activation. Activated MCs export S1P into the extracellular space and causes inflammatory response and tissue remodeling. S1P signaling has dual role in allergic responses. Activation of SphKs and secretion of S1P are required for MC activation; however, S1P signaling plays a vital role in the recovery from anaphylaxis. Several non-coding RNAs have been shown to play a crucial role in controlling the MC-associated inflammatory and allergic responses. Thus, S1P signaling pathway and its regulation by non-coding RNA could be explored as an exciting potential therapeutic target for asthma and other MC-associated diseases.

  19. The role of sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) in the trafficking of normal and malignant cells

    Ratajczak, Mariusz Z.; Suszynska, Malwina; Borkowska, Sylwia; Ratajczak, Janina; Schneider, Gabriela

    2014-01-01

    Introduction A common feature of many types of cells is their responsiveness to chemotactic gradients of factors for which they express the corresponding receptors. The most studied chemoattractants so far are peptide-based growth factors and a family of cytokines endowed with strong chemotactic properties, called chemokines. However, additional evidence has accumulated that, in addition to these peptide-based chemoattractants, an important role in cell migration is played by bioactive lipids. Areas covered Solid evidence has accumulated that two bioactive phosphorylated sphingolipids that are derivatives of sphingolipid metabolism, namely sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P), are potent chemoattractants for a variety of cells. In this review, we will discuss the effect of these two phosphorylated sphingolipids on the trafficking of normal and malignant cells, and, in particular, we will focus on their role in trafficking of normal hematopoietic stem/progenitor cells. Unlike other mediators, S1P under steady state conditions maintain a steep gradient between interstitial fluid and peripheral blood and lymph across the endothelial barrier, which is important in the egress of cells from bone marrow. Both S1P and C1P may be upregulated in damaged tissues, which may result in reversal of this gradient. Expert opinion S1P and C1P are important regulators of the trafficking of normal and malignant cells, and modification of their biological effects will have important applications in optimizing stem cell mobilization and homing, tissue organ/regeneration, and preventing cancer metastasis. PMID:24188167

  20. Sphingosine-1-Phosphate Metabolism and Its Role in the Development of Inflammatory Bowel Disease

    Tomasz Wollny

    2017-03-01

    Full Text Available Beyond their role as structural molecules, sphingolipids are involved in many important cellular processes including cell proliferation, apoptosis, inflammation, and migration. Altered sphingolipid metabolism is observed in many pathological conditions including gastrointestinal diseases. Inflammatory bowel disease (IBD represents a state of complex, unpredictable, and destructive inflammation of unknown origin within the gastrointestinal tract. The mechanisms explaining the pathophysiology of IBD involve signal transduction pathways regulating gastro-intestinal system’s immunity. Progressive intestinal tissue destruction observed in chronic inflammation may be associated with an increased risk of colon cancer. Sphingosine-1-phosphate (S1P, a sphingolipid metabolite, functions as a cofactor in inflammatory signaling and becomes a target in the treatment of IBD, which might prevent its conversion to cancer. This paper summarizes new findings indicating the impact of (S1P on IBD development and IBD-associated carcinogenesis.

  1. SPHINGOSINE-1 PHOSPHATE: A NEW MODULATOR OF IMMUNE PLASTICITY IN THE TUMOR MICROENVIRONMENT

    Yamila I Rodriguez

    2016-10-01

    Full Text Available In the last 15 years, increasing evidences demonstrate a strong link between sphingosine-1-phosphate (S1P in both normal physiology and progression of different diseases, including cancer and inflammation. Indeed, numerous studies show that tissue levels of this sphingolipid metabolite are augmented in many cancers, affecting survival, proliferation, angiogenesis and metastatic spread. Recent insights into the possible role of S1P as a therapeutic target has attracted enormous attention and opened new opportunities in this evolving field. In this review we will focus on the role of S1P in cancer with particular emphasis in new developments that highlight the many functions of this sphingolipid in the tumor microenvironment. We will discuss how S1P modulates phenotypic plasticity of macrophages and mast cells, tumor-induced immune evasion, differentiation and survival of immune cells in the tumor milieu, interaction between cancer and stromal cells and hypoxic response.

  2. The Transporter Spns2 Is Required for Secretion of Lymph but Not Plasma Sphingosine-1-Phosphate

    Alejandra Mendoza

    2012-11-01

    Full Text Available Plasma sphingosine-1-phosphate (S1P regulates vascular permeability, and plasma and lymph S1P guide lymphocyte egress from lymphoid organs. S1P is made intracellularly, and little is known about how S1P is delivered into circulatory fluids. Here, we find that mice without the major facilitator superfamily transporter Spns2 have a profound reduction in lymph S1P, but only a minor decrease in plasma S1P. Spns2-deficient mice have a redistribution of lymphocytes from the spleen to lymph nodes and a loss of circulating lymphocytes, consistent with normal egress from the spleen directed by plasma S1P and blocked egress from lymph nodes directed by lymph S1P. Spns2 is needed in endothelial cells to supply lymph S1P and support lymphocyte circulation. As a differential requirement for lymph and blood S1P, Spns2 may be an attractive target for immune suppressive drugs.

  3. Sphingosine-1-Phosphate (S1P)-Related Response of Human Conjunctival Fibroblasts After Filtration Surgery for Glaucoma.

    Aoyama-Araki, Yuka; Honjo, Megumi; Uchida, Takatoshi; Yamagishi, Reiko; Kano, Kuniyuki; Aoki, Junken; Aihara, Makoto

    2017-04-01

    To investigate levels of sphingosine-1-phosphate (S1P) in aqueous fluid samples taken before and after filtration surgery and S1P-induced human conjunctival fibroblast (HCF) responses. Levels of S1P and its related sphingophospholipids in aqueous fluid obtained immediately before and after filtration surgery were determined by liquid chromatography-tandem mass spectrometry. HCFs were used for all in vitro experiments. The expression of five S1P receptor subtypes in HCFs was examined by quantitative real-time PCR. The effect of S1P and receptor-specific antagonists on HCF viability and cell migration was assessed by WST-1 assay and scratch migration assay, respectively. Differentiation to myofibroblasts and extracellular matrix production was evaluated by examining changes in F-actin, α-smooth muscle actin (αSMA), and collagen expression with immunocytochemistry, Western blotting, and collagen accumulation assay, respectively. No significant S1P levels in the aqueous fluid samples were detectable immediately before surgery, but postoperative levels of several lysophospholipids, including S1P, dehydro-S1P, and sphingosine, were significantly increased to bioactive concentrations in aqueous fluid in the blebs (P S1P receptor subtypes was detected in HCFs. Although S1P levels did not influence HCF proliferation, S1P enhanced cell migration, which could be inhibited by the S1P2 antagonist JTE 013. F-actin, αSMA, and collagen expression was significantly increased by S1P stimulation and was reduced by JTE 013. Bioactive S1P concentrations were present in the aqueous fluid at the end of filtration surgery. S1P activated HCFs via S1P2 receptors. These results revealed the potential of S1P2 antagonists in preventing scarring after glaucoma filtration surgery.

  4. Sphingosine-1-phosphate regulates RGS2 and RGS16 mRNA expression in vascular smooth muscle cells

    Hendriks-Balk, Mariëlle C.; Hajji, Najat; van Loenen, Pieter B.; Michel, Martin C.; Peters, Stephan L. M.; Alewijnse, Astrid E.

    2009-01-01

    Regulator of G protein signalling (RGS) protein expression is altered under growth promoting conditions in vascular smooth muscle cells (VSMCs). Since sphingosine-1-phosphate (S1P) is an important growth stimulatory factor, we investigated whether stimulation of VSMCs with S1P results in alterations

  5. Inflammatory lipid sphingosine-1-phosphate upregulates C-reactive protein via C/EBPβ and potentiates breast cancer progression

    Kim, E.S.; Cha, Y.; Ham, M.; Jung, J.; Kim, S.G.; Hwang, S.; Kleemann, R.; Moon, A.

    2014-01-01

    A crucial role of the inflammatory lipid sphingosine-1-phosphate (S1P) in breast cancer aggressiveness has been reported. Recent clinical studies have suggested that C-reactive protein (CRP) has a role in breast cancer development. However, limited information is available on the molecular basis for

  6. Decreased plasma levels of the endothelial protective sphingosine-1-phosphate are associated with dengue-induced plasma leakage

    Michels, M.; Japtok, L.; Alisjahbana, B.; Wisaksana, R.; Sumardi, U.; Puspita, M.; Kleuser, B.; Mast, Q. de; Ven, A.J.A.M. van der

    2015-01-01

    BACKGROUND: A transient endothelial hyperpermeability is a hallmark of severe dengue infections. Sphingosine-1-phosphate (S1P) maintains vascular integrity and protects against plasma leakage. We related plasma S1P levels to dengue-induced plasma leakage and studied mechanisms that may underlie the

  7. TNF-α production in NKT cell hybridoma is regulated by sphingosine-1-phosphate: implications for inflammation in atherosclerosis.

    Ito, Shiori; Iwaki, Soichiro; Kondo, Rie; Satoh, Masashi; Iwabuchi, Kazuya; Ohkawa, Ryunosuke; Mishima, Yuko; Yatomi, Yutaka; Furumoto, Tomoo; Tsutsui, Hiroyuki; Fujii, Satoshi

    2014-06-01

    Natural killer T (NKT) cells are unique T lymphocytes that recognize glycolipid antigen and produce various cytokines. NKT cells accelerate atherosclerosis in mice. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid and regulates T-lymphocyte trafficking. We aimed to determine the effects of S1P on the production of proinflammatory cytokine, tumor necrosis factor (TNF)-α, in NKT cell hybridomas and mouse NKT cells. NKT cell hybridomas and sorted mouse NKT cells were stimulated with S1P and α-galactosylceramide (α-GalCer), the major ligand to produce cytokines in NKT cells. TNF-α mRNA expression and protein production were determined by real-time PCR and ELISA, respectively. Cell migration was assayed using chemotaxicell. Plasma S1P was measured using HPLC. Hybridomas expressed S1P receptors, S1P1, S1P2, and S1P4. S1P and α-GalCer increased TNF-α mRNA expression and protein production. S1P enhanced TNF-α induction by α-GalCer. S1P receptor antagonists decreased the TNF-α mRNA expression induced by S1P. FTY720, an immunosuppressive S1P receptor modulator, also decreased the TNF-α mRNA expression. The migration of NKT cell hybridomas was increased by S1P. FTY720 reduced the migration induced by S1P. S1P also increased the TNF-α mRNA expression in mouse NKT cells. Plasma TNF-α levels in patients with high plasma S1P (≥500 nmol/l) were higher than those in patients with low S1P (NKT cells and enhances TNF-α production. TNF-α overproduction may induce atherogenic inflammatory responses. S1P may serve as a novel therapeutic target for amelioration of vascular inflammatory diseases.

  8. Sphingosine-1-Phosphate (S1P) Lyase Inhibition Causes Increased Cardiac S1P Levels and Bradycardia in Rats.

    Harris, Christopher M; Mittelstadt, Scott; Banfor, Patricia; Bousquet, Peter; Duignan, David B; Gintant, Gary; Hart, Michelle; Kim, Youngjae; Segreti, Jason

    2016-10-01

    Inhibition of the sphingosine-1-phosphate (S1P)-catabolizing enzyme S1P lyase (S1PL) elevates the native ligand of S1P receptors and provides an alternative mechanism for immune suppression to synthetic S1P receptor agonists. S1PL inhibition is reported to preferentially elevate S1P in lymphoid organs. Tissue selectivity could potentially differentiate S1PL inhibitors from S1P receptor agonists, the use of which also results in bradycardia, atrioventricular block, and hypertension. But it is unknown if S1PL inhibition would also modulate cardiac S1P levels or cardiovascular function. The S1PL inhibitor 6-[(2R)-4-(4-benzyl-7-chlorophthalazin-1-yl)-2-methylpiperazin-1-yl]pyridine-3-carbonitrile was used to determine the relationship in rats between drug concentration, S1P levels in select tissues, and circulating lymphocytes. Repeated oral doses of the S1PL inhibitor fully depleted circulating lymphocytes after 3 to 4 days of treatment in rats. Full lymphopenia corresponded to increased levels of S1P of 100- to 1000-fold in lymph nodes, 3-fold in blood (but with no change in plasma), and 9-fold in cardiac tissue. Repeated oral dosing of the S1PL inhibitor in telemeterized, conscious rats resulted in significant bradycardia within 48 hours of drug treatment, comparable in magnitude to the bradycardia induced by 3 mg/kg fingolimod. These results suggest that S1PL inhibition modulates cardiac function and does not provide immune suppression with an improved cardiovascular safety profile over fingolimod in rats. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  9. Sphingosine-1-Phosphate (S1P) and S1P Signaling Pathway: Therapeutic Targets in Autoimmunity and Inflammation.

    Tsai, Hsing-Chuan; Han, May H

    2016-07-01

    Sphingosine-1-phosphate (S1P) and S1P receptors (S1PR) are ubiquitously expressed. S1P-S1PR signaling has been well characterized in immune trafficking and activation in innate and adaptive immune systems. However, the full extent of its involvement in the pathogenesis of autoimmune diseases is not well understood. FTY720 (fingolimod), a non-selective S1PR modulator, significantly decreased annualized relapse rates in relapsing-remitting multiple sclerosis (MS). FTY720, which primarily targets S1P receptor 1 as a functional antagonist, arrests lymphocyte egress from secondary lymphoid tissues and reduces neuroinflammation in the central nervous system (CNS). Recent studies suggest that FTY720 also decreases astrogliosis and promotes oligodendrocyte differentiation within the CNS and may have therapeutic benefit to prevent brain atrophy. Since S1P signaling is involved in multiple immune functions, therapies targeting S1P axis may be applicable to treat autoimmune diseases other than MS. Currently, over a dozen selective S1PR and S1P pathway modulators with potentially superior therapeutic efficacy and better side-effect profiles are in the pipeline of drug development. Furthermore, newly characterized molecules such as apolipoprotein M (ApoM) (S1P chaperon) and SPNS2 (S1P transporter) are also potential targets for treatment of autoimmune diseases. Finally, the application of therapies targeting S1P and S1P signaling pathways may be expanded to treat several other immune-mediated disorders (such as post-infectious diseases, post-stroke and post-stroke dementia) and inflammatory conditions beyond their application in primary autoimmune diseases.

  10. Sphingosine-1-phosphate enhances satellite cell activation in dystrophic muscles through a S1PR2/STAT3 signaling pathway.

    Kenneth C Loh

    Full Text Available Sphingosine-1-phosphate (S1P activates a widely expressed family of G protein-coupled receptors, serves as a muscle trophic factor and activates muscle stem cells called satellite cells (SCs through unknown mechanisms. Here we show that muscle injury induces dynamic changes in S1P signaling and metabolism in vivo. These changes include early and profound induction of the gene encoding the S1P biosynthetic enzyme SphK1, followed by induction of the catabolic enzyme sphingosine phosphate lyase (SPL 3 days later. These changes correlate with a transient increase in circulating S1P levels after muscle injury. We show a specific requirement for SphK1 to support efficient muscle regeneration and SC proliferation and differentiation. Mdx mice, which serve as a model for muscular dystrophy (MD, were found to be S1P-deficient and exhibited muscle SPL upregulation, suggesting that S1P catabolism is enhanced in dystrophic muscle. Pharmacological SPL inhibition increased muscle S1P levels, improved mdx muscle regeneration and enhanced SC proliferation via S1P receptor 2 (S1PR2-dependent inhibition of Rac1, thereby activating Signal Transducer and Activator of Transcription 3 (STAT3, a central player in inflammatory signaling. STAT3 activation resulted in p21 and p27 downregulation in a S1PR2-dependent fashion in myoblasts. Our findings suggest that S1P promotes SC progression through the cell cycle by repression of cell cycle inhibitors via S1PR2/STAT3-dependent signaling and that SPL inhibition may provide a therapeutic strategy for MD.

  11. Circulating levels of sphingosine-1-phosphate are elevated in severe, but not mild psoriasis and are unresponsive to anti-TNF-α treatment

    Checa, Antonio; Xu, Ning; Sar, Daniel G.; Haeggström, Jesper Z.; Ståhle, Mona; Wheelock, Craig E.

    2015-07-01

    Sphingolipids are bioactive molecules with a putative role in inflammation. Alterations in sphingolipids, in particular ceramides, have been consistently observed in psoriatic skin. Herein, we quantified the circulating sphingolipid profile in individuals with mild or severe psoriasis as well as healthy controls. In addition, the effects of anti-TNF-α treatment were determined. Levels of sphingoid bases, including sphingosine-1-phosphate (S1P), increased in severe (P S1P response to treatment may have pathobiological implications due to its close relation to the vascular and immune systems. In particular, increased levels of sphingolipids and especially S1P in severe psoriasis patients requiring biological treatment may potentially be associated with cardiovascular comorbidities. The fact that shifts in S1P levels were not ameliorated by anti-TNF-α treatment, despite improvements in the skin lesions, further supports targeting S1P receptors as therapy for severe psoriasis.

  12. Sphingosine-1-Phosphate as a Regulator of Hypoxia-Induced Factor-1α in Thyroid Follicular Carcinoma Cells.

    Veronica Kalhori

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive lipid, which regulates several cancer-related processes including migration and angiogenesis. We have previously shown S1P to induce migration of follicular ML-1 thyroid cancer cells. Hypoxia-induced factor-1 (HIF-1 is an oxygen-sensitive transcription factor, which adapts cells to hypoxic conditions through increased survival, motility and angiogenesis. Due to these properties and its increased expression in response to intratumoral hypoxia, HIF-1 is considered a significant regulator of tumor biology. We found S1P to increase expression of the regulatory HIF-1α subunit in normoxic ML-1 cells. S1P also increased HIF-1 activity and expression of HIF-1 target genes. Importantly, inhibition or knockdown of HIF-1α attenuated the S1P-induced migration of ML-1 cells. S1P-induced HIF-1α expression was mediated by S1P receptor 3 (S1P3, Gi proteins and their downstream effectors MEK, PI3K, mTOR and PKCβI. Half-life measurements with cycloheximide indicated that S1P treatment stabilized the HIF-1α protein. On the other hand, S1P activated translational regulators eIF-4E and p70S6K, which are known to control HIF-1α synthesis. In conclusion, we have identified S1P as a non-hypoxic regulator of HIF-1 activity in thyroid cancer cells, studied the signaling involved in S1P-induced HIF-1α expression and shown S1P-induced migration to be mediated by HIF-1.

  13. Sphingosine-1-Phosphate as a Regulator of Hypoxia-Induced Factor-1α in Thyroid Follicular Carcinoma Cells

    Asghar, Muhammad Yasir; Bergelin, Nina; Jaakkola, Panu; Törnquist, Kid

    2013-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid, which regulates several cancer-related processes including migration and angiogenesis. We have previously shown S1P to induce migration of follicular ML-1 thyroid cancer cells. Hypoxia-induced factor-1 (HIF-1) is an oxygen-sensitive transcription factor, which adapts cells to hypoxic conditions through increased survival, motility and angiogenesis. Due to these properties and its increased expression in response to intratumoral hypoxia, HIF-1 is considered a significant regulator of tumor biology. We found S1P to increase expression of the regulatory HIF-1α subunit in normoxic ML-1 cells. S1P also increased HIF-1 activity and expression of HIF-1 target genes. Importantly, inhibition or knockdown of HIF-1α attenuated the S1P-induced migration of ML-1 cells. S1P-induced HIF-1α expression was mediated by S1P receptor 3 (S1P3), Gi proteins and their downstream effectors MEK, PI3K, mTOR and PKCβI. Half-life measurements with cycloheximide indicated that S1P treatment stabilized the HIF-1α protein. On the other hand, S1P activated translational regulators eIF-4E and p70S6K, which are known to control HIF-1α synthesis. In conclusion, we have identified S1P as a non-hypoxic regulator of HIF-1 activity in thyroid cancer cells, studied the signaling involved in S1P-induced HIF-1α expression and shown S1P-induced migration to be mediated by HIF-1. PMID:23824493

  14. Oxidized LDL-induced angiogenesis involves sphingosine 1-phosphate: prevention by anti-S1P antibody.

    Camaré, Caroline; Trayssac, Magali; Garmy-Susini, Barbara; Mucher, Elodie; Sabbadini, Roger; Salvayre, Robert; Negre-Salvayre, Anne

    2015-01-01

    Neovascularization occurring in atherosclerotic lesions may promote plaque expansion, intraplaque haemorrhage and rupture. Oxidized LDL (oxLDL) are atherogenic, but their angiogenic effect is controversial; both angiogenic and anti-angiogenic effects have been reported. The angiogenic mechanism of oxLDL is partly understood, but the role of the angiogenic sphingolipid, sphingosine 1-phosphate (S1P), in this process is not known. Thus, we investigated whether S1P is involved in the oxLDL-induced angiogenesis and whether an anti-S1P monoclonal antibody can prevent this effect. Angiogenesis was assessed by capillary tube formation by human microvascular endothelial cells (HMEC-1) cultured on Matrigel and in vivo by the Matrigel plug assay in C57BL/6 mice. Human oxLDL exhibited a biphasic angiogenic effect on HMEC-1; low concentrations were angiogenic, higher concentrations were cytotoxic. The angiogenic response to oxLDL was blocked by the sphingosine kinase (SPHK) inhibitor, dimethylsphingosine, by SPHK1-siRNA and by an anti-S1P monoclonal antibody. Moreover, inhibition of oxLDL uptake and subsequent redox signalling by anti-CD36 and anti-LOX-1 receptor antibodies and by N-acetylcysteine, respectively, blocked SPHK1 activation and tube formation. In vivo, in the Matrigel plug assay, low concentrations of human oxLDL or murine oxVLDL also triggered angiogenesis, which was prevented by i.p. injection of the anti-S1P antibody. These data highlight the role of S1P in angiogenesis induced by oxLDL both in HMEC-1 cultured on Matrigel and in vivo in the Matrigel plug model in mice, and demonstrate that the anti-S1P antibody effectively blocks the angiogenic effect of oxLDL. © 2014 The British Pharmacological Society.

  15. Exogenous sphingosine-1-phosphate boosts acclimatization in rats exposed to acute hypobaric hypoxia: assessment of haematological and metabolic effects.

    Sonam Chawla

    Full Text Available The physiological challenges posed by hypobaric hypoxia warrant exploration of pharmacological entities to improve acclimatization to hypoxia. The present study investigates the preclinical efficacy of sphingosine-1-phosphate (S1P to improve acclimatization to simulated hypobaric hypoxia.Efficacy of intravenously administered S1P in improving haematological and metabolic acclimatization was evaluated in rats exposed to simulated acute hypobaric hypoxia (7620 m for 6 hours following S1P pre-treatment for three days.Altitude exposure of the control rats caused systemic hypoxia, hypocapnia (plausible sign of hyperventilation and respiratory alkalosis due to suboptimal renal compensation indicated by an overt alkaline pH of the mixed venous blood. This was associated with pronounced energy deficit in the hepatic tissue along with systemic oxidative stress and inflammation. S1P pre-treatment improved blood oxygen-carrying-capacity by increasing haemoglobin, haematocrit, and RBC count, probably as an outcome of hypoxia inducible factor-1α mediated erythropoiesis and renal S1P receptor 1 mediated haemoconcentation. The improved partial pressure of oxygen in the blood could further restore aerobic respiration and increase ATP content in the hepatic tissue of S1P treated animals. S1P could also protect the animals from hypoxia mediated oxidative stress and inflammation.The study findings highlight S1P's merits as a preconditioning agent for improving acclimatization to acute hypobaric hypoxia exposure. The results may have long term clinical application for improving physiological acclimatization of subjects venturing into high altitude for occupational or recreational purposes.

  16. S1P receptor signalling and RGS proteins; expression and function in vascular smooth muscle cells and transfected CHO cells

    Hendriks-Balk, Mariëlle C.; van Loenen, Pieter B.; Hajji, Najat; Michel, Martin C.; Peters, Stephan L. M.; Alewijnse, Astrid E.

    2009-01-01

    Sphingosine-1-phosphate (S1P) signalling via G protein-coupled receptors is important for the regulation of cell function and differentiation. Specific Regulators of G protein Signalling (RGS) proteins modulate the function of these receptors in many cell types including vascular smooth muscle cells

  17. Sphingosine 1-phosphate promotes activation of aprine preantral follicle in vitro

    J.E. Nóbrega Jr.

    2014-08-01

    Full Text Available This study describes the effect of sphingosine 1-phosphate (S1P for development of preantral follicle, therefore the activation and follicular viability of caprine follicles cultured in vitro. Ovarian fragments were cultured for 1 or 7 days in Minimum Essential Medium with different S1P concentrations (0, 1, 10, 50, 100 or 200ng/mL. All ovarian fragments were processed for histological analysis in optical microscopy, transmission electron microscopy and fluorescence analysis. The treatment using 1ng/mL of S1P was able to maintain the percentage of normal follicles with the progression of the culture from day 1 to 7. At end of the 7-day culture period there was a significant reduction (P<0.05 in the percentage of primordial follicles in all groups treated with S1P, compared with fresh control (FC and Control Culture (CC, which was followed by an increase of activated follicles (intermediary, primary and secondary. In addition, the culture for 7 days with media supplemented with S1P with 1ng/mL preserved the ultrastructure of organelles and kept the preantral follicular viability when evaluated by fluorescence microscopy. In conclusion, after 7 days of culture, the 1ng/mL of S1P activates the development of preantral caprine follicles, cultured in situ and maintains the oocitary and follicular viability.

  18. Sphingosine kinase/sphingosine 1-phosphate axis: a new player for insulin-like growth factor-1-induced myoblast differentiation

    Bernacchioni Caterina

    2012-07-01

    Full Text Available Abstract Background Insulin-like growth factor-1 (IGF-1 is the most important physiological regulator of skeletal muscle progenitor cells, which are responsible for adult skeletal muscle regeneration. The ability of IGF-1 to affect multiple aspects of skeletal muscle cell biology such as proliferation, differentiation, survival and motility is well recognized, although the molecular mechanisms implicated in its complex biological action are not fully defined. Since sphingosine 1-phosphate (S1P has recently emerged as a key player in skeletal muscle regeneration, we investigated the possible involvement of the sphingosine kinase (SK/S1P receptor axis on the biological effects of IGF-1 in murine myoblasts. Methods RNA interference, chemical inhibition and immunofluorescence approaches were used to assess the role of the SK/S1P axis on the myogenic and mitogenic effects of IGF-1 in C2C12 myoblasts. Results We show that IGF-1 increases SK activity in mouse myoblasts. The effect of the growth factor does not involve transcriptional regulation of SK1 or SK2, since the protein content of both isoforms is not affected; rather, IGF-1 enhances the fraction of the active form of SK. Moreover, transactivation of the S1P2 receptor induced by IGF-1 via SK activation appears to be involved in the myogenic effect of the growth factor. Indeed, the pro-differentiating effect of IGF-1 in myoblasts is impaired when SK activity is pharmacologically inhibited, or SK1 or SK2 are specifically silenced, or the S1P2 receptor is downregulated. Furthermore, in this study we show that IGF-1 transactivates S1P1/S1P3 receptors via SK activation and that this molecular event negatively regulates the mitogenic effect elicited by the growth factor, since the specific silencing of S1P1 or S1P3 receptors increases cell proliferation induced by IGF-1. Conclusions We demonstrate a dual role of the SK/S1P axis in response to myoblast challenge with IGF-1, that likely is important to

  19. Native and reconstituted HDL activate Stat3 in ventricular cardiomyocytes via ERK1/2: role of sphingosine-1-phosphate.

    Frias, Miguel A; James, Richard W; Gerber-Wicht, Christine; Lang, Ursula

    2009-05-01

    High-density lipoprotein (HDL) has been reported to have cardioprotective properties independent from its cholesterol transport activity. The influence of native HDL and reconstituted HDL (rHDL) on Stat3, the transcription factor playing an important role in myocardium adaptation to stress, was analysed in neonatal rat ventricular cardiomyocytes. We have investigated modulating the composition of rHDL as a means of expanding its function and potential cardioprotective effects. Stat3 phosphorylation and activation were determined by western blotting and electrophoretic mobility shift assay (EMSA). In ventricular cardiomyocytes, HDL and the HDL constituent sphingosine-1-phosphate (S1P) induce a concentration- and time-dependent increase in Stat3 activation. They also enhance extracellular signal-regulated kinases (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) phosphorylation. U0126, a specific inhibitor of MEK1/2, the upstream activator of ERK1/2, abolishes HDL- and S1P-induced Stat3 activation, whereas the p38 MAPK blocker SB203580 has no significant effect. Inhibition of the tyrosine kinase family Src (Src) caused a significant reduction of Stat3 activation, whereas inhibition of phosphatidylinositol 3-kinase (PI3K) had no effect. S1P and rHDL containing S1P have a similar strong stimulatory action on Stat3, ERK1/2, and p38 MAPK comparable to native HDL. S1P-free rHDL has a much weaker effect. Experiments with agonists and antagonists of the S1P receptor subtypes indicate that HDL and S1P activate Stat3 mainly through the S1P2 receptor. In ventricular cardiomyocytes, addition of S1P to rHDL enhances its therapeutic potential by improving its capacity to activate Stat3. Activation of Stat3 occurs mainly via the S1P constituent and the lipid receptor S1P2 requiring stimulation of ERK1/2 and Src but not p38 MAPK or PI3K. The study underlines the therapeutic potential of tailoring rHDL to confront particular clinical situations.

  20. Partial deficiency of sphingosine-1-phosphate lyase confers protection in experimental autoimmune encephalomyelitis.

    Andreas Billich

    Full Text Available BACKGROUND: Sphingosine-1-phosphate (S1P regulates the egress of T cells from lymphoid organs; levels of S1P in the tissues are controlled by S1P lyase (Sgpl1. Hence, Sgpl1 offers a target to block T cell-dependent inflammatory processes. However, the involvement of Sgpl1 in models of disease has not been fully elucidated yet, since Sgpl1 KO mice have a short life-span. METHODOLOGY: We generated inducible Sgpl1 KO mice featuring partial reduction of Sgpl1 activity and analyzed them with respect to sphingolipid levels, T-cell distribution, and response in models of inflammation. PRINCIPAL FINDINGS: The partially Sgpl1 deficient mice are viable but feature profound reduction of peripheral T cells, similar to the constitutive KO mice. While thymic T cell development in these mice appears normal, mature T cells are retained in thymus and lymph nodes, leading to reduced T cell numbers in spleen and blood, with a skewing towards increased proportions of memory T cells and T regulatory cells. The therapeutic relevance of Sgpl1 is demonstrated by the fact that the inducible KO mice are protected in experimental autoimmune encephalomyelitis (EAE. T cell immigration into the CNS was found to be profoundly reduced. Since S1P levels in the brain of the animals are unchanged, we conclude that protection in EAE is due to the peripheral effect on T cells, leading to reduced CNS immigration, rather than on local effects in the CNS. SIGNIFICANCE: The data suggest Sgpl1 as a novel therapeutic target for the treatment of multiple sclerosis.

  1. Regeneration of glycocalyx by heparan sulfate and sphingosine 1-phosphate restores inter-endothelial communication.

    Solomon A Mensah

    Full Text Available Vasculoprotective endothelium glycocalyx (GCX shedding plays a critical role in vascular disease. Previous work demonstrated that GCX degradation disrupts endothelial cell (EC gap junction connexin (Cx proteins, likely blocking interendothelial molecular transport that maintains EC and vascular tissue homeostasis to resist disease. Here, we focused on GCX regeneration and tested the hypothesis that vasculoprotective EC function can be stimulated via replacement of GCX when it is shed. We used EC with [i] intact heparan sulfate (HS, the most abundant GCX component; [ii] degraded HS; or [iii] HS that was restored after enzyme degradation, by cellular self-recovery or artificially. Artificial HS restoration was achieved via treatment with exogenous HS, with or without the GCX regenerator and protector sphingosine 1- phosphate (S1P. In these cells we immunocytochemically examined expression of Cx isotype 43 (Cx43 at EC borders and characterized Cx-containing gap junction activity by measuring interendothelial spread of gap junction permeable Lucifer Yellow dye. With intact HS, 60% of EC borders expressed Cx43 and dye spread to 2.88 ± 0.09 neighboring cells. HS degradation decreased Cx43 expression to 30% and reduced dye spread to 1.87± 0.06 cells. Cellular self-recovery of HS restored baseline levels of Cx43 and dye transfer. Artificial HS recovery with exogenous HS partially restored Cx43 expression to 46% and yielded dye spread to only 1.03 ± 0.07 cells. Treatment with both HS and S1P, recovered HS and restored Cx43 to 56% with significant dye transfer to 3.96 ± 0.23 cells. This is the first evidence of GCX regeneration in a manner that effectively restores vasculoprotective EC communication.

  2. Targeting sphingosine-1-phosphate lyase as an anabolic therapy for bone loss.

    Weske, Sarah; Vaidya, Mithila; Reese, Alina; von Wnuck Lipinski, Karin; Keul, Petra; Bayer, Julia K; Fischer, Jens W; Flögel, Ulrich; Nelsen, Jens; Epple, Matthias; Scatena, Marta; Schwedhelm, Edzard; Dörr, Marcus; Völzke, Henry; Moritz, Eileen; Hannemann, Anke; Rauch, Bernhard H; Gräler, Markus H; Heusch, Gerd; Levkau, Bodo

    2018-05-01

    Sphingosine-1-phosphate (S1P) signaling influences bone metabolism, but its therapeutic potential in bone disorders has remained unexplored. We show that raising S1P levels in adult mice through conditionally deleting or pharmacologically inhibiting S1P lyase, the sole enzyme responsible for irreversibly degrading S1P, markedly increased bone formation, mass and strength and substantially decreased white adipose tissue. S1P signaling through S1P 2 potently stimulated osteoblastogenesis at the expense of adipogenesis by inversely regulating osterix and PPAR-γ, and it simultaneously inhibited osteoclastogenesis by inducing osteoprotegerin through newly discovered p38-GSK3β-β-catenin and WNT5A-LRP5 pathways. Accordingly, S1P 2 -deficient mice were osteopenic and obese. In ovariectomy-induced osteopenia, S1P lyase inhibition was as effective as intermittent parathyroid hormone (iPTH) treatment in increasing bone mass and was superior to iPTH in enhancing bone strength. Furthermore, lyase inhibition in mice successfully corrected severe genetic osteoporosis caused by osteoprotegerin deficiency. Human data from 4,091 participants of the SHIP-Trend population-based study revealed a positive association between serum levels of S1P and bone formation markers, but not resorption markers. Furthermore, serum S1P levels were positively associated with serum calcium , negatively with PTH , and curvilinearly with body mass index. Bone stiffness, as determined through quantitative ultrasound, was inversely related to levels of both S1P and the bone formation marker PINP, suggesting that S1P stimulates osteoanabolic activity to counteract decreasing bone quality. S1P-based drugs should be considered as a promising therapeutic avenue for the treatment of osteoporotic diseases.

  3. Fluorescence-based rapid measurement of sphingosine-1-phosphate transport activity in erythrocytes[S

    Kobayashi, Naoki; Otsuka, Masato; Yamaguchi, Akihito; Nishi, Tsuyoshi

    2016-01-01

    Sphingosine-1-phosphate (S1P) is present in the blood plasma and acts as a pivotal intercellular signal transmitter in the immune system by recruiting lymphocytes from the thymus and secondary lymphoid tissues. The plasma S1P concentration is maintained by the supply of S1P from erythrocytes. Previously, we showed that S1P release from erythrocytes is mediated by an ATP-dependent transporter. In this study, we attempted to establish a rapid and reliable method for measuring the S1P transport activity in erythrocytes by using a fluorescent S1P analog, 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD)-labeled S1P. NBD-S1P was released from erythrocytes in a time-dependent manner. The NBD-S1P release was reduced after exposure to glyburide, which is an inhibitor of the S1P transporter in erythrocytes. Moreover, the release of NBD-S1P and S1P from erythrocytes was competitively inhibited by intracellular S1P and NBD-S1P, respectively. These results showed that the erythrocyte S1P transporter exports NBD-S1P. We optimized the sample-preparation conditions and lipid extraction to increase the sensitivity of the assay. Furthermore, we successfully measured NBD-S1P release without lipid extraction by decreasing the concentration of BSA in the assay buffer to 0.1%. This method will be useful for the high-throughput screening of S1P transporter inhibitors using conventional fluorometers. PMID:27655910

  4. Sphingosine 1-phosphate induces neutrophil chemoattractant IL-8: repression by steroids.

    Md Mostafizur Rahman

    Full Text Available The bioactive sphingolipid sphingosine 1-phosphate (S1P is found in increased amounts in the airways of asthmatics. S1P can regulate airway smooth muscle functions associated with asthmatic inflammation and remodeling, including cytokine secretion. To date however, whether S1P induces secretion of an important chemokine responsible for neutrophilia in airway inflammation--IL-8--was unexplored. The aim of this study was to investigate whether S1P induces IL-8 gene expression and secretion to enhance neutrophil chemotaxis in vitro, as well as examine the molecular mechanisms responsible for repression by the corticosteroid dexamethasone. We show that S1P upregulates IL-8 secretion from ASM cells and enhance neutrophil chemotaxis in vitro. The corticosteroid dexamethasone significantly represses IL-8 mRNA expression and protein secretion in a concentration- and time-dependent manner. Additionally, we reveal that S1P-induced IL-8 secretion is p38 MAPK and ERK-dependent and that these key phosphoproteins act on the downstream effector mitogen- and stress-activated kinase 1 (MSK1 to control secretion of the neutrophil chemoattractant cytokine IL-8. The functional relevance of this in vitro data was demonstrated by neutrophil chemotaxis assays where S1P-induced effects can be significantly attenuated by pretreatment with dexamethasone, pharmacological inhibition of p38 MAPK- or ERK-mediated pathways, or by knocking down MSK-1 with siRNA. Taken together, our study reveals the molecular pathways responsible for IL-8 secretion from ASM cells in response to S1P and indicates ways in which the impact on IL-8-driven neutrophilia may be lessened.

  5. Serum-Sphingosine-1-Phosphate Concentrations Are Inversely Associated with Atherosclerotic Diseases in Humans.

    Irina Soltau

    Full Text Available Atherosclerotic changes of arteries are the leading cause for deaths in cardiovascular disease and greatly impair patient's quality of life. Sphingosine-1-phosphate (S1P is a signaling sphingolipid that regulates potentially pro-as well as anti-atherogenic processes. Here, we investigate whether serum-S1P concentrations are associated with peripheral artery disease (PAD and carotid stenosis (CS.Serum was sampled from blood donors (controls, N = 174 and from atherosclerotic patients (N = 132 who presented to the hospital with either clinically relevant PAD (N = 102 or CS (N = 30. From all subjects, serum-S1P was measured by mass spectrometry and blood parameters were determined by routine laboratory assays. When compared to controls, atherosclerotic patients before invasive treatment to restore blood flow showed significantly lower serum-S1P levels. This difference cannot be explained by risk factors for atherosclerosis (old age, male gender, hypertension, hypercholesteremia, obesity, diabetes or smoking or comorbidities (Chronic obstructive pulmonary disease, kidney insufficiency or arrhythmia. Receiver operating characteristic curves suggest that S1P has more power to indicate atherosclerosis (PAD and CS than high density lipoprotein-cholesterol (HDL-C. In 35 patients, serum-S1P was measured again between one and six months after treatment. In this group, serum-S1P concentrations rose after treatment independent of whether patients had PAD or CS, or whether they underwent open or endovascular surgery. Post-treatment S1P levels were highly associated to platelet numbers measured pre-treatment.Our study shows that PAD and CS in humans is associated with decreased serum-S1P concentrations and that S1P may possess higher accuracy to indicate these diseases than HDL-C.

  6. Combination of ciclopirox olamine and sphingosine-1-phosphate as granulation enhancer in diabetic wounds.

    Lim, Natalie Sheng Jie; Sham, Adeline; Chee, Stella Min Ling; Chan, Casey; Raghunath, Michael

    2016-09-01

    Granulation tissue formation requires a robust angiogenic response. As granulation tissue develops, collagen fibers are deposited and compacted. Forces generated in the wake of this process drive wound contraction to reduce the wound area. In diabetics, both angiogenesis and wound contraction are diminished leading to impaired wound healing. To emulate this pathology and to address it pharmacologically, we developed a wound healing model in the diabetic Zucker fatty rat and tested a topical proangiogenic strategy combining antifungal agent ciclopirox olamine (CPX) and lysophospholipid sphingosine-1-phosphate (S1P) to promote diabetic wound closure. In vitro, we demonstrated that CPX + S1P up-regulates a crucial driver of angiogenesis, hypoxia-inducible factor-1, in endothelial cells. Injection of CPX + S1P into subcutaneously implanted sponges in experimental rats showed, in an additive manner, a fivefold increased endothelial infiltration and lectin-perfused vessel length. We developed a splinted diabetic rodent model to achieve low wound contraction rates that are characteristic for the healing mode of diabetic ulcers in humans. We discovered specific dorsal sites that allowed for incremental full-thickness excisional wound depths from 1 mm (superficial) to 3 mm (deep). This enabled us to bring down wound contraction from 51% in superficial wounds to 8% in deep wounds. While the effects of topical gel treatment of CPX + S1P were masked by the rodent-characteristic dominant contraction in superficial wounds, they became clearly evident in deep diabetic wounds. Here, a fivefold increase of functional large vessels resulted in accelerated granulation tissue formulation, accompanied by a 40% increase of compacted thick collagen fibers. This was associated with substantially reduced matrix metalloproteinase-3 and -13 expression. These findings translated into a fivefold increase in granulation-driven contraction, promoting diabetic wound closure. With CPX

  7. Sphingosine-1-phosphate prevents chemotherapy-induced human primordial follicle death.

    Li, Fang; Turan, Volkan; Lierman, Sylvie; Cuvelier, Claude; De Sutter, Petra; Oktay, Kutluk

    2014-01-01

    Can Sphingosine-1-phosphate (S1P), a ceramide-induced death pathway inhibitor, prevent cyclophosphamide (Cy) or doxorubicin (Doxo) induced apoptotic follicle death in human ovarian xenografts? S1P can block human apoptotic follicle death induced by both drugs, which have differing mechanisms of cytotoxicity. S1P has been shown to decrease the impact of chemotherapy and radiation on germinal vesicle oocytes in animal studies but no human translational data exist. Experimental human ovarian xenografting to test the in vivo protective effect of S1P on primordial follicle survival in the chemotherapy setting. The data were validated by assessing the same protective effect in the ovaries of xenografted mice in parallel. Xenografted mice were treated with Cy (75 mg/kg), Cy+S1P (200 μM), Doxo (10 mg/kg), Doxo+S1P or vehicle only (Control). S1P was administered via continuous infusion using a mini-osmotic pump beginning 24 h prior to and ending 72 h post-chemotherapy. Grafts were then recovered and stained with anti-caspase 3 antibody for the detection of apoptosis in primordial follicles. The percentage of apoptotic to total primordial follicles was calculated in each group. Both Cy and Doxo resulted in a significant increase in apoptotic follicle death in human ovarian xenografts compared with controls (62.0 ± 3.9% versus 25.7 ± 7.4%, P 0.05). The findings from the ovaries of the severe combined immunodeficient mice mirrored the findings with human tissue. The functionality of the rescued human ovarian follicles needs to be evaluated in future studies though the studies in rodents showed that rescued oocytes can result in healthy offspring. In addition, the impact of S1P on cancer cells should be further studied. S1P and its future analogs hold promise for preserving fertility by pharmacological means for patients undergoing chemotherapy. This research is supported by NIH's NICHD and NCI (5R01HD053112-06 and 5R21HD061259-02) and the Flemish Foundation for Scientific

  8. Sphingosine-1-phosphate/sphingosine-1-phosphate receptor 1 signaling is required for migration of naive human T cells from the thymus to the periphery

    Resop, Rachel S.; Douaisi, Marc; Craft, Joshua; Jachimowski, Loes C. M.; Blom, Bianca; Uittenbogaart, Christel H.

    2016-01-01

    The mechanisms that govern the egress of mature thymocytes from the human thymus to the periphery remain understudied yet are of utmost importance to the field of basic immunology, as well as T-cell reconstitution in various immunodeficiencies. We examined the expression and function of

  9. Mechanism of sphingosine 1-phosphate- and lysophosphatidic Acid-induced up-regulation of adhesion molecules and eosinophil chemoattractant in nerve cells.

    Costello, Richard W

    2012-02-01

    The lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) act via G-protein coupled receptors S1P(1-5) and LPA(1-3) respectively, and are implicated in allergy. Eosinophils accumulate at innervating cholinergic nerves in asthma and adhere to nerve cells via intercellular adhesion molecule-1 (ICAM-1). IMR-32 neuroblastoma cells were used as an in vitro cholinergic nerve cell model. The G(i) coupled receptors S1P(1), S1P(3), LPA(1), LPA(2) and LPA(3) were expressed on IMR-32 cells. Both S1P and LPA induced ERK phosphorylation and ERK- and G(i)-dependent up-regulation of ICAM-1 expression, with differing time courses. LPA also induced ERK- and G(i)-dependent up-regulation of the eosinophil chemoattractant, CCL-26. The eosinophil granule protein eosinophil peroxidase (EPO) induced ERK-dependent up-regulation of transcription of S1P(1), LPA(1), LPA(2) and LPA(3), providing the situation whereby eosinophil granule proteins may enhance S1P- and\\/or LPA- induced eosinophil accumulation at nerve cells in allergic conditions.

  10. Mechanism of sphingosine 1-phosphate- and lysophosphatidic Acid-induced up-regulation of adhesion molecules and eosinophil chemoattractant in nerve cells.

    Costello, Richard W

    2011-05-01

    The lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) act via G-protein coupled receptors S1P(1-5) and LPA(1-3) respectively, and are implicated in allergy. Eosinophils accumulate at innervating cholinergic nerves in asthma and adhere to nerve cells via intercellular adhesion molecule-1 (ICAM-1). IMR-32 neuroblastoma cells were used as an in vitro cholinergic nerve cell model. The G(i) coupled receptors S1P(1), S1P(3), LPA(1), LPA(2) and LPA(3) were expressed on IMR-32 cells. Both S1P and LPA induced ERK phosphorylation and ERK- and G(i)-dependent up-regulation of ICAM-1 expression, with differing time courses. LPA also induced ERK- and G(i)-dependent up-regulation of the eosinophil chemoattractant, CCL-26. The eosinophil granule protein eosinophil peroxidase (EPO) induced ERK-dependent up-regulation of transcription of S1P(1), LPA(1), LPA(2) and LPA(3), providing the situation whereby eosinophil granule proteins may enhance S1P- and\\/or LPA- induced eosinophil accumulation at nerve cells in allergic conditions.

  11. Data on subgroup specific baseline characteristics and serum sphingosine-1-phosphate concentrations in the Study of Health in Pomerania

    Eileen Moritz

    2017-06-01

    Full Text Available In this data article, we provide subgroup specific baseline characteristics and serum sphingosine-1-phosphate (S1P concentrations for healthy individuals within the Study of Health in Pomerania (SHIP-TREND cohort. After exclusion of subjects with cardiovascular disease, diabetes mellitus, hypertension, metabolic syndrome, elevated liver enzymes and/or chronic kidney disease stadium III or IV, four subgroups were defined according to different limits for body mass index (BMI, alterations in blood lipid levels and smoking status. Tables show respective clinical and laboratory parameters stratified by gender. Serum S1P concentrations are also stratified by age groups. The data presented herein is related to the research article entitled “Reference intervals for serum sphingosine-1-phosphate in the population-based Study of Health in Pomerania” (E. Moritz, D. Wegner, S. Groß, M. Bahls, M. Dörr, S.B. Felix, T. Ittermann, S. Oswald, M. Nauck, N. Friedrich, R.H. Böger, G. Daum, E. Schwedhelm, B.H. Rauch, Clin Chim Acta. 468 (2017 25–31 [1].

  12. Manipulating Endothelial Progenitor Cell Homing with Sphingosine-1-Phosphate for Terapeutic Angiogenesis

    Williams, Priscilla Anne

    Ischemic vascular diseases are the main cause of mortality worldwide and yet current therapies only delay disease progression and improve quality of life without addressing the fundamental problem of tissue loss. Within the field of tissue engineering, therapeutic angiogenesis provides a promising approach to alternatively provide new blood vessel formation via spatiotemporally controlled delivery of proangiogenic agents. Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid that is upregulated under ischemic conditions, has recently gained great enthusiasm as a potential mediator in neovascularization strategies given its essential roles in promoting both neovessel formation and stabilization, and cellular trafficking along highly regulated endogenous gradients. Herein, the governing hypothesis guiding this dissertation is that local biomaterial-controlled delivery of S1P may be used to enhance migration and recruitment of vascular progenitor cells for enhanced therapeutic angiogenesis within ischemic tissue. The initial work in this dissertation investigated the effect of hypoxia on the angiogenic response of both mature and progenitor endothelial cells to S1P stimulation in vitro. Outgrowth endothelial cells (OECs) were isolated from human umbilical cord blood to provide a clinically relevant source of vascular progenitor cells for the studies conducted within this dissertation. S1P stimulation promoted angiogenic activity of both ECs and OECs under both ambient and hypoxic (1%) oxygen tensions. Furthermore, dual therapy with the combination of S1P and vascular endothelial growth factor (VEGF) further enhanced cellular responses. Interestingly, hypoxia substantially augmented the functional response of OECs to S1P, resulting in 25-fold and 6.5-fold increases in directed migration and sprouting, respectively. Thus, these studies highlighted the potential for S1P as a therapeutic agent for treatment of ischemic diseases. An injectable biomaterial system

  13. Sphingosine 1-Phosphate Induces Platelet/Endothelial Cell Adhesion Molecule-1 Tyrosine Phosphorylation in Bovine Aortic Endothelial Cells through a PP2-Inhibitable Mechanism

    Yu-Ting Huang

    2007-12-01

    Full Text Available Sphingosine-1-phosphate (S1P is a low-molecular-weight phospholipid derivative released by activated platelets. S1P transduces signals through a family of G protein-coupled receptors to modulate various physiological behaviors of endothelial cells. Platelet/endothelial cell adhesion molecule-1 (PECAM-1; CD31 is a 130-kDa protein expressed on the surfaces of leukocytes, platelets, and endothelial cells. Upon PECAM-1 activation, its cytoplasmic tyrosine residues become phosphorylated and bind with SH2 domain-containing proteins, thus leading to the downstream functions mediated by PECAM-1. In the present study, we found that S1P induced PECAM-1 tyrosine phosphorylation and SHP-2 association in bovine aortic endothelial cells (BAECs by immunoprecipitation and western blotting. The pretreatment of BAECs with a series of chemical inhibitors to determine the signaling pathway showed that the PECAM-1 phosphorylation was inhibited by PP2, indicating the participation of Src family kinases. These results demonstrated that S1P induced PECAM-1 tyrosine phosphorylation in BAECs through mediation of Src family kinases, and this may regulate the physiological behaviors of endothelial cells.

  14. A rapid and validated HPLC method to quantify sphingosine 1-phosphate in human plasma using solid-phase extraction followed by derivatization with fluorescence detection

    Butter, Jan J.; Koopmans, Richard P.; Michel, Martin C.

    2005-01-01

    We describe the development and validation of analytical methodology for the determination of sphingosine 1-phosphate (S1P) in plasma. It uses solid-phase extraction (SPE) followed by an automated reversed-phase gradient HPLC column-switching system with a pre-column derivatization with

  15. High density lipoprotein (HDL)-associated sphingosine 1-phosphate (S1P) inhibits macrophage apoptosis by stimulating STAT3 activity and survivin expression

    Feuerborn, Renata; Becker, Susen; Potì, Francesco

    2017-01-01

    BACKGROUND AND AIMS: Macrophage apoptosis is critically involved in atherosclerosis. We here examined the effect of anti-atherogenic high density lipoprotein (HDL) and its component sphingosine-1-phosphate (S1P) on apoptosis in RAW264.7 murine macrophages. METHODS: Mitochondrial or endoplasmic re...

  16. Exosomes from Human-Induced Pluripotent Stem Cell-Derived Mesenchymal Stromal Cells (hiPSC-MSCs) Protect Liver against Hepatic Ischemia/ Reperfusion Injury via Activating Sphingosine Kinase and Sphingosine-1-Phosphate Signaling Pathway.

    Du, Yingdong; Li, Dawei; Han, Conghui; Wu, Haoyu; Xu, Longmei; Zhang, Ming; Zhang, Jianjun; Chen, Xiaosong

    2017-01-01

    This study aimed to evaluate the effects of exosomes produced by human-induced pluripotent stem cell-derived mesenchymal stromal cells (hiPSC-MSCs-Exo) on hepatic ischemia-reperfusion (I/R) injury, as well as the underlying mechanisms. Exosomes derived from hiPSC-MSCs were isolated and characterized both biochemically and biophysically. hiPSC-MSCs-Exo were injected systemically into a murine ischemia/reperfusion injury model via the inferior vena cava, and then the therapeutic effects were evaluated. The serum levels of transaminases (aspartate aminotransferase (AST) and alanine aminotransferase (ALT), as well as histological changes were examined. Primary hepatocytes and human hepatocyte cell line HL7702 were used to test whether exosomes could induce hepatocytes proliferation in vitro. In addition, the expression levels of proliferation markers (proliferation cell nuclear antigen, PCNA; Phosphohistone-H3, PHH3) were measured by immunohistochemistry and Western blot. Moreover, SK inhibitor (SKI-II) and S1P1 receptor antagonist (VPC23019) were used to investigate the role of sphingosine kinase and sphingosine-1-phosphate-dependent pathway in the effects of hiPSC-MSCs-Exo on hepatocytes. hiPSCs were efficiently induced into hiPSC-MSCs that had typical MSC characteristics. hiPSC-MSCs-Exo had diameters ranging from 100 to 200 nm and expressed exosome markers (Alix, CD63 and CD81). After hiPSC-MSCs-Exo administration, hepatocyte necrosis and sinusoidal congestion were markedly suppressed in the ischemia/reperfusion injury model, with lower histopathological scores. The levels of hepatocyte injury markers AST and ALT were significantly lower in the treatment group compared to control, and the expression levels of proliferation markers (PCNA and PHH3) were greatly induced after hiPSC-MSCs-Exo administration. Moreover, hiPSC-MSCs-Exo also induced primary hepatocytes and HL7702 cells proliferation in vitro in a dose-dependent manner. We found that hiPSC-MSCs-Exo could

  17. Sphingosine 1-Phosphate Activation of EGFR As a Novel Target for Meningitic Escherichia coli Penetration of the Blood-Brain Barrier

    Wang, Xiangru; Maruvada, Ravi; Morris, Andrew J.; Liu, Jun O.; Baek, Dong Jae; Kim, Kwang Sik

    2016-01-01

    Central nervous system (CNS) infection continues to be an important cause of mortality and morbidity, necessitating new approaches for investigating its pathogenesis, prevention and therapy. Escherichia coli is the most common Gram-negative bacillary organism causing meningitis, which develops following penetration of the blood–brain barrier (BBB). By chemical library screening, we identified epidermal growth factor receptor (EGFR) as a contributor to E. coli invasion of the BBB in vitro. Here, we obtained the direct evidence that CNS-infecting E. coli exploited sphingosine 1-phosphate (S1P) for EGFR activation in penetration of the BBB in vitro and in vivo. We found that S1P was upstream of EGFR and participated in EGFR activation through S1P receptor as well as through S1P-mediated up-regulation of EGFR-related ligand HB-EGF, and blockade of S1P function through targeting sphingosine kinase and S1P receptor inhibited EGFR activation, and also E. coli invasion of the BBB. We further found that both S1P and EGFR activations occurred in response to the same E. coli proteins (OmpA, FimH, NlpI), and that S1P and EGFR promoted E. coli invasion of the BBB by activating the downstream c-Src. These findings indicate that S1P and EGFR represent the novel host targets for meningitic E. coli penetration of the BBB, and counteracting such targets provide a novel approach for controlling E. coli meningitis in the era of increasing resistance to conventional antibiotics. PMID:27711202

  18. Sphingosine-1-Phosphate Induces Dose-Dependent Chemotaxis or Fugetaxis of T-ALL Blasts through S1P1 Activation

    Messias, Carolina V.; Santana-Van-Vliet, Eliane; Lemos, Julia P.; Moreira, Otacilio C.; Cotta-de-Almeida, Vinicius; Savino, Wilson; Mendes-da-Cruz, Daniella Arêas

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5). S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL) did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM) did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000–10000 nM) through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts. PMID:26824863

  19. Sphingosine-1-Phosphate Induces Dose-Dependent Chemotaxis or Fugetaxis of T-ALL Blasts through S1P1 Activation.

    Carolina V Messias

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5. S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000-10000 nM through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts.

  20. Epigenetic regulation of pro-inflammatory cytokine secretion by sphingosine 1-phosphate (S1P) in acute lung injury: Role of S1P lyase.

    Ebenezer, David L; Fu, Panfeng; Suryadevara, Vidyani; Zhao, Yutong; Natarajan, Viswanathan

    2017-01-01

    Cellular level of sphingosine-1-phosphate (S1P), the simplest bioactive sphingolipid, is tightly regulated by its synthesis catalyzed by sphingosine kinases (SphKs) 1 & 2 and degradation mediated by S1P phosphatases, lipid phosphate phosphatases, and S1P lyase. The pleotropic actions of S1P are attributed to its unique inside-out (extracellular) signaling via G-protein-coupled S1P1-5 receptors, and intracellular receptor independent signaling. Additionally, S1P generated in the nucleus by nuclear SphK2 modulates HDAC1/2 activity, regulates histone acetylation, and transcription of pro-inflammatory genes. Here, we present data on the role of S1P lyase mediated S1P signaling in regulating LPS-induced inflammation in lung endothelium. Blocking S1P lyase expression or activity attenuated LPS-induced histone acetylation and secretion of pro-inflammatory cytokines. Degradation of S1P by S1P lyase generates Δ2-hexadecenal and ethanolamine phosphate and the long-chain fatty aldehyde produced in the cytoplasmic compartment of the endothelial cell seems to modulate histone acetylation pattern, which is different from the nuclear SphK2/S1P signaling and inhibition of HDAC1/2. These in vitro studies suggest that S1P derived long-chain fatty aldehyde may be an epigenetic regulator of pro-inflammatory genes in sepsis-induced lung inflammation. Trapping fatty aldehydes and other short chain aldehydes such as 4-hydroxynonenal derived from S1P degradation and lipid peroxidation, respectively by cell permeable agents such as phloretin or other aldehyde trapping agents may be useful in treating sepsis-induced lung inflammation via modulation of histone acetylation. . Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. High density lipoprotein (HDL)-associated sphingosine 1-phosphate (S1P) inhibits macrophage apoptosis by stimulating STAT3 activity and survivin expression.

    Feuerborn, Renata; Becker, Susen; Potì, Francesco; Nagel, Petra; Brodde, Martin; Schmidt, Harmut; Christoffersen, Christina; Ceglarek, Uta; Burkhardt, Ralph; Nofer, Jerzy-Roch

    2017-02-01

    Macrophage apoptosis is critically involved in atherosclerosis. We here examined the effect of anti-atherogenic high density lipoprotein (HDL) and its component sphingosine-1-phosphate (S1P) on apoptosis in RAW264.7 murine macrophages. Mitochondrial or endoplasmic reticulum-dependent apoptosis was induced by exposure of macrophages to etoposide or thapsigargin/fukoidan, respectively. Cell death induced by these compounds was inhibited by S1P as inferred from reduced annexin V binding, TUNEL staining, and caspase 3, 9 and 12 activities. S1P induced expression of the inhibitor of apoptosis protein (IAP) family proteins cIAP1, cIAP2 and survivin, but only the inhibitor of survivin expression YM155 and not the cIAP1/2 blocker GDC0152 reversed the inhibitory effect of S1P on apoptosis. Moreover, S1P activated signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2 (JAK2) and the stimulatory effect of S1P on survivin expression and inhibitory effects on apoptosis were attenuated by STAT3 or JAK2 inhibitors, S3I-201 or AG490, respectively. The effects of S1P on STAT3 activation, survivin expression and macrophage apoptosis were emulated by HDL, HDL lipids, and apolipoprotein (apo) M-containing HDL, but not by apoA-I or HDL deprived of S1P or apoM. In addition, JTE013 and CAY10444, S1P receptor 2 and 3 antagonists, respectively, compromised the S1P and HDL capacities to stimulate STAT3 activation and survivin expression, and to inhibit apoptosis. HDL-associated S1P inhibits macrophage apoptosis by stimulating STAT3 activity and survivin expression. The suppression of macrophage apoptosis may represent a novel mechanism utilized by HDL to exert its anti-atherogenic effects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. New extracellular factors in glioblastoma multiforme development: neurotensin, growth differentiation factor-15, sphingosine-1-phosphate and cytomegalovirus infection

    Korbecki, Jan; Gutowska, Izabela; Kojder, Ireneusz; Jeżewski, Dariusz; Goschorska, Marta; Łukomska, Agnieszka; Lubkowska, Anna; Chlubek, Dariusz; Baranowska-Bosiacka, Irena

    2018-01-01

    Recent years have seen considerable progress in understanding the biochemistry of cancer. For example, more significance is now assigned to the tumor microenvironment, especially with regard to intercellular signaling in the tumor niche which depends on many factors secreted by tumor cells. In addition, great progress has been made in understanding the influence of factors such as neurotensin, growth differentiation factor-15 (GDF-15), sphingosine-1-phosphate (S1P), and infection with cytomegalovirus (CMV) on the ‘hallmarks of cancer’ in glioblastoma multiforme. Therefore, in the present work we describe the influence of these factors on the proliferation and apoptosis of neoplastic cells, cancer stem cells, angiogenesis, migration and invasion, and cancer immune evasion in a glioblastoma multiforme tumor. In particular, we discuss the effect of neurotensin, GDF-15, S1P (including the drug FTY720), and infection with CMV on tumor-associated macrophages (TAM), microglial cells, neutrophil and regulatory T cells (Treg), on the tumor microenvironment. In order to better understand the role of the aforementioned factors in tumoral processes, we outline the latest models of intratumoral heterogeneity in glioblastoma multiforme. Based on the most recent reports, we discuss the problems of multi-drug therapy in treating glioblastoma multiforme. PMID:29467963

  3. Mesenchymal Stromal Cell Secreted Sphingosine 1-Phosphate (S1P) Exerts a Stimulatory Effect on Skeletal Myoblast Proliferation

    Tani, Alessia; Anderloni, Giulia; Pierucci, Federica; Matteini, Francesca; Chellini, Flaminia; Zecchi Orlandini, Sandra; Meacci, Elisabetta

    2014-01-01

    Bone-marrow-derived mesenchymal stromal cells (MSCs) have the potential to significantly contribute to skeletal muscle healing through the secretion of paracrine factors that support proliferation and enhance participation of the endogenous muscle stem cells in the process of repair/regeneration. However, MSC-derived trophic molecules have been poorly characterized. The aim of this study was to investigate paracrine signaling effects of MSCs on skeletal myoblasts. It was found, using a biochemical and morphological approach that sphingosine 1-phosphate (S1P), a natural bioactive lipid exerting a broad range of muscle cell responses, is secreted by MSCs and represents an important factor by which these cells exert their stimulatory effects on C2C12 myoblast and satellite cell proliferation. Indeed, exposure to conditioned medium obtained from MSCs cultured in the presence of the selective sphingosine kinase inhibitor (iSK), blocked increased cell proliferation caused by the conditioned medium from untreated MSCs, and the addition of exogenous S1P in the conditioned medium from MSCs pre-treated with iSK further increased myoblast proliferation. Finally, we also demonstrated that the myoblast response to MSC-secreted vascular endothelial growth factor (VEGF) involves the release of S1P from C2C12 cells. Our data may have important implications in the optimization of cell-based strategies to promote skeletal muscle regeneration. PMID:25264785

  4. Sphingosine 1-phosphate-induced ICAM-1 expression via NADPH oxidase/ROS-dependent NF-kappaB cascade on human pulmonary alveolar epithelial cells

    Chin-Chung eLin

    2016-03-01

    Full Text Available The intercellular adhesion molecule-1 (ICAM-1 expression is frequently correlated with the lung inflammation. A bioactive sphingolipid metabolite, sphingosine-1-phosphate (S1P, was involved in inflammation through the adhesion molecules induction, and then caused lung injury. However, the transduction mechanisms of the S1P stimulation to induce ICAM-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs remain unclear. Here, we demonstrated that exposure of HPAEpiCs to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCdelta, PF431396 (PYK2, diphenyleneiodonium chloride (DPI, apocynin (NADPH oxidase, Edaravone (ROS, and Bay11-7082 (NF-kappaB. Consistently, knockdown with siRNA transfection of PKCdelta, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A and Gi/o-coupled receptor antagonist (GPA2 also blocked S1P-induced ICAM-1 protein and mRNA expression. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCdelta-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-kappaB p65 phosphorylation and translocation from the cytosol to the nucleus in HPAEpiCs, which was inhibited by Rottlerin, PF431396, APO, DPI, or Edaravone. In the in vitro study, we established that S1P induced monocyte adhesion via an ICAM-1-dependent pathway. In the in vivo study, we found that S1P induced ICAM-1 protein and mRNA levels in the lung fractions, pulmonary hematoma, and leukocyte (mainly eosinophils and neutrophils count in bronchoalveolar lavage (BAL fluid in mice via a PKCdelta/PYK2/NADPH oxidase/ROS/NF-kappaB signaling pathway. We concluded that S1P may induce lung

  5. Sphingosine 1-Phosphate-Induced ICAM-1 Expression via NADPH Oxidase/ROS-Dependent NF-κB Cascade on Human Pulmonary Alveolar Epithelial Cells

    Lin, Chih-Chung; Yang, Chien-Chung; Cho, Rou-Ling; Wang, Chen-Yu; Hsiao, Li-Der; Yang, Chuen-Mao

    2016-01-01

    The intercellular adhesion molecule-1 (ICAM-1) expression is frequently correlated with the lung inflammation. In lung injury, sphingosine-1-phosphate (S1P, bioactive sphingolipid metabolite), participate gene regulation of adhesion molecule in inflammation progression and aggravate tissue damage. To investigate the transduction mechanisms of the S1P in pulmonary epithelium, we demonstrated that exposure of HPAEpiCs (human pulmonary alveolar epithelial cells) to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCδ), PF431396 (PYK2), diphenyleneiodonium chloride (DPI), apocynin (NADPH oxidase), Edaravone (ROS), and Bay11-7082 (NF-κB). Consistently, knockdown with siRNA transfection of PKCδ, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A) and Gi/o-coupled receptor antagonist (GPA2) also blocked the upregulation of ICAM-1 protein and mRNA induced by S1P. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCδ-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-κB p65 phosphorylation and nuclear translocation in HPAEpiCs. Activated NF-κB was blocked by Rottlerin, PF431396, APO, DPI, or Edaravone. Besides, the results of monocyte adhesion assay indicated that S1P-induced ICAM-1 expression on HPAEpiCs can enhance the monocyte attachments. In the S1P-treated mice, we found that the levels of ICAM-1 protein and mRNA in the lung fractions, the pulmonary hematoma and leukocyte count in bronchoalveolar lavage fluid were enhanced through a PKCδ/PYK2/NADPH oxidase/ROS/NF-κB signaling pathway. We concluded that S1P-accelerated lung damage is due to the ICAM-1 induction associated with

  6. Targeting Sphingosine-1-Phosphate Axis in Obesity-Promoted Breast Cancer

    2016-05-01

    5 5. Changes/Problems...….……………………………………………… 6 6. Products …………………………………….……….….……………. 6 7. Participants & Other...Unfortunately, half of these patients will ultimately fail therapy due to de novo or acquired resistance as well as patients with ER, progesterone receptor...cytokine and chemokine production , among others (Pyne and Pyne 2010, Spiegel and Milstien 2011). Although many of the actions of S1P are mediated by

  7. Sphingosine-1-phosphate (S1P) enhances glomerular endothelial cells activation mediated by anti-myeloperoxidase antibody-positive IgG.

    Sun, Xiao-Jing; Chen, Min; Zhao, Ming-Hui

    2018-03-01

    Cumulating evidences suggested an important role of sphingosine-1-phosphate (S1P) and its receptors in regulating endothelial barrier integrity. Our previous study revealed that the circulating S1P levels and renal expression of S1PRs correlated with disease activity and renal damage in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study investigated the role of S1P and its receptors in myeloperoxidase (MPO)-ANCA-positive IgG-mediated glomerular endothelial cell (GEnC) activation. The effect of S1P on morphological alteration of GEnCs in the presence of MPO-ANCA-positive IgG was observed. Permeability assay was performed to determine endothelial monolayer activation in quantity. Both membrane-bound and soluble ICAM-1 and VCAM-1 levels were measured. Furthermore, antagonists and/or agonists of various S1PRs were employed to determine the role of different S1PRs. S1P enhanced MPO-ANCA-positive IgG-induced disruption of tight junction and disorganization of cytoskeleton in GEnCs. S1P induced further increase in monolayer permeability of GEnC monolayers in the presence of MPO-ANCA-positive IgG. S1P enhanced MPO-ANCA-positive IgG-induced membrane-bound and soluble ICAM-1/VCAM-1 up-regulation of GEnCs. Soluble ICAM-1 levels in the supernatants of GEnCs stimulated by S1P and MPO-ANCA-positive IgG increased upon pre-incubation of S1PR1 antagonist, while pre-incubation of GEnCs with the S1PR1 agonist down-regulated sICAM-1 level. Blocking S1PR2-4 reduced sICAM-1 levels in the supernatants of GEnCs stimulated by S1P and MPO-ANCA-positive IgG. Pre-incubation with S1PR5 agonist could increase sICAM-1 level in the supernatants of GEnC stimulated by S1P and MPO-ANCA-positive IgG. S1P can enhance MPO-ANCA-positive IgG-mediated GEnC activation through S1PR2-5. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  8. Determination of Sphingosine-1-Phosphate in Human Plasma Using Liquid Chromatography Coupled with Q-Tof Mass Spectrometry

    Egom, Emmanuel E.; Fitzgerald, Ross; Canning, Rebecca; Pharithi, Rebabonye B.; Murphy, Colin; Maher, Vincent

    2017-01-01

    Evidence suggests that high-density lipoprotein (HDL) components distinct from cholesterol, such as sphingosine-1-phosphate (S1P), may account for the anti-atherothrombotic effects attributed to this lipoprotein. The current method for the determination of plasma levels of S1P as well as levels associated with HDL particles is still cumbersome an assay method to be worldwide practical. Recently, a simplified protocol based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the sensitive and specific quantification of plasma levels of S1P with good accuracy has been reported. This work utilized a triple quadrupole (QqQ)-based LC-MS/MS system. Here we adapt that method for the determination of plasma levels of S1P using a quadrupole time of flight (Q-Tof) based LC-MS system. Calibration curves were linear in the range of 0.05 to 2 µM. The lower limit of quantification (LOQ) was 0.05 µM. The concentration of S1P in human plasma was determined to be 1 ± 0.09 µM (n = 6). The average accuracy over the stated range of the method was found to be 100 ± 5.9% with precision at the LOQ better than 10% when predicting the calibration standards. The concentration of plasma S1P in the prepared samples was stable for 24 h at room temperature. We have demonstrated the quantification of plasma S1P using Q-Tof based LC-MS with very good sensitivity, accuracy, and precision that can used for future studies in this field. PMID:28820460

  9. Structural and Functional Insight of Sphingosine 1-Phosphate-Mediated Pathogenic Metabolic Reprogramming in Sickle Cell Disease.

    Sun, Kaiqi; D'Alessandro, Angelo; Ahmed, Mostafa H; Zhang, Yujin; Song, Anren; Ko, Tzu-Ping; Nemkov, Travis; Reisz, Julie A; Wu, Hongyu; Adebiyi, Morayo; Peng, Zhangzhe; Gong, Jing; Liu, Hong; Huang, Aji; Wen, Yuan Edward; Wen, Alexander Q; Berka, Vladimir; Bogdanov, Mikhail V; Abdulmalik, Osheiza; Han, Leng; Tsai, Ah-Lim; Idowu, Modupe; Juneja, Harinder S; Kellems, Rodney E; Dowhan, William; Hansen, Kirk C; Safo, Martin K; Xia, Yang

    2017-11-10

    Elevated sphingosine 1-phosphate (S1P) is detrimental in Sickle Cell Disease (SCD), but the mechanistic basis remains obscure. Here, we report that increased erythrocyte S1P binds to deoxygenated sickle Hb (deoxyHbS), facilitates deoxyHbS anchoring to the membrane, induces release of membrane-bound glycolytic enzymes and in turn switches glucose flux towards glycolysis relative to the pentose phosphate pathway (PPP). Suppressed PPP causes compromised glutathione homeostasis and increased oxidative stress, while enhanced glycolysis induces production of 2,3-bisphosphoglycerate (2,3-BPG) and thus increases deoxyHbS polymerization, sickling, hemolysis and disease progression. Functional studies revealed that S1P and 2,3-BPG work synergistically to decrease both HbA and HbS oxygen binding affinity. The crystal structure at 1.9 Å resolution deciphered that S1P binds to the surface of 2,3-BPG-deoxyHbA and causes additional conformation changes to the T-state Hb. Phosphate moiety of the surface bound S1P engages in a highly positive region close to α1-heme while its aliphatic chain snakes along a shallow cavity making hydrophobic interactions in the "switch region", as well as with α2-heme like a molecular "sticky tape" with the last 3-4 carbon atoms sticking out into bulk solvent. Altogether, our findings provide functional and structural bases underlying S1P-mediated pathogenic metabolic reprogramming in SCD and novel therapeutic avenues.

  10. Sphingosine-1-phosphate promotes the differentiation of human umbilical cord mesenchymal stem cells into cardiomyocytes under the designated culturing conditions

    Zhang Henggui

    2011-06-01

    Full Text Available Abstract Background It is of growing interest to develop novel approaches to initiate differentiation of mesenchymal stem cells (MSCs into cardiomyocytes. The purpose of this investigation was to determine if Sphingosine-1-phosphate (S1P, a native circulating bioactive lipid metabolite, plays a role in differentiation of human umbilical cord mesenchymal stem cells (HUMSCs into cardiomyocytes. We also developed an engineered cell sheet from these HUMSCs derived cardiomyocytes by using a temperature-responsive polymer, poly(N-isopropylacrylamide (PIPAAm cell sheet technology. Methods Cardiomyogenic differentiation of HUMSCs was performed by culturing these cells with either designated cardiomyocytes conditioned medium (CMCM alone, or with 1 μM S1P; or DMEM with 10% FBS + 1 μM S1P. Cardiomyogenic differentiation was determined by immunocytochemical analysis of expression of cardiomyocyte markers and patch clamping recording of the action potential. Results A cardiomyocyte-like morphology and the expression of α-actinin and myosin heavy chain (MHC proteins can be observed in both CMCM culturing or CMCM+S1P culturing groups after 5 days' culturing, however, only the cells in CMCM+S1P culture condition present cardiomyocyte-like action potential and voltage gated currents. A new approach was used to form PIPAAm based temperature-responsive culture surfaces and this successfully produced cell sheets from HUMSCs derived cardiomyocytes. Conclusions This study for the first time demonstrates that S1P potentiates differentiation of HUMSCs towards functional cardiomyocytes under the designated culture conditions. Our engineered cell sheets may provide a potential for clinically applicable myocardial tissues should promote cardiac tissue engineering research.

  11. Sphingosine-1-phosphate (S1P) activates STAT3 to protect against de novo acute heart failure (AHF).

    Deshpande, Gaurang P; Imamdin, Aqeela; Lecour, Sandrine; Opie, Lionel H

    2018-03-01

    Acute heart failure (AHF) is a burden disease, with high mortality and re-hospitalisations. Using an ex-vivo model of AHF, we have previously reported that sphingosine-1-phosphate (S1P) confers cardioprotection. However, the mechanisms remain to be elucidated. In the present study, we aimed to examine the role of the cardioprotective signal transducer and activator of transcription 3 (STAT3) in S1P mediated improved functional recovery in AHF. Isolated hearts from male Long-Evans rats were subjected to hypotensive AHF for 35 min followed by a recovery phase of 30 min (n ≥ 4/group). S1P (10 nM) was given during either the hypotensive or the recovery phase with/without an inhibitor of STAT3, AG490. Functional parameters were recorded throughout the experiment. Following an AHF insult, S1P, given during the recovery phase, improved the heart rate (HR) compared to the control (175.2 ± 30.7 vs. 71.6 ± 27.4 beats per minute (BPM); p S1P abolished the cardioprotective effect of S1P (42.3 ± 17.1 vs. 148.8 ± 26.4 BPM for S1P; p S1P protects in an ex-vivo rat heart model of AHF by activation of STAT3 and provide further evidence for the usage of S1P as a potential therapy in patients suffering from AHF. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Increased sphingosine-1-phosphate improves muscle regeneration in acutely injured mdx mice

    2013-01-01

    Background Presently, there is no effective treatment for the lethal muscle wasting disease Duchenne muscular dystrophy (DMD). Here we show that increased sphingosine-1-phoshate (S1P) through direct injection or via the administration of the small molecule 2-acetyl-4(5)-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, has beneficial effects in acutely injured dystrophic muscles of mdx mice. Methods We treated mdx mice with and without acute injury and characterized the histopathological and functional effects of increasing S1P levels. We also tested exogenous and direct administration of S1P on mdx muscles to examine the molecular pathways under which S1P promotes regeneration in dystrophic muscles. Results Short-term treatment with THI significantly increased muscle fiber size and extensor digitorum longus (EDL) muscle specific force in acutely injured mdx limb muscles. In addition, the accumulation of fibrosis and fat deposition, hallmarks of DMD pathology and impaired muscle regeneration, were lower in the injured muscles of THI-treated mdx mice. Furthermore, increased muscle force was observed in uninjured EDL muscles with a longer-term treatment of THI. Such regenerative effects were linked to the response of myogenic cells, since intramuscular injection of S1P increased the number of Myf5nlacz/+ positive myogenic cells and newly regenerated myofibers in injured mdx muscles. Intramuscular injection of biotinylated-S1P localized to muscle fibers, including newly regenerated fibers, which also stained positive for S1P receptor 1 (S1PR1). Importantly, plasma membrane and perinuclear localization of phosphorylated S1PR1 was observed in regenerating muscle fibers of mdx muscles. Intramuscular increases of S1P levels, S1PR1 and phosphorylated ribosomal protein S6 (P-rpS6), and elevated EDL muscle specific force, suggest S1P promoted the upregulation of anabolic pathways that mediate skeletal muscle mass and function. Conclusions These data show that S1P is

  13. Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles.

    Hernández-Coronado, C G; Guzmán, A; Espinosa-Cervantes, R; Romano, M C; Verde-Calvo, J R; Rosales-Torres, A M

    2015-02-01

    The follicle destiny towards ovulation or atresia is multi-factorial in nature and involves outcries, paracrine and endocrine factors that promote cell proliferation and survival (development) or unchain apoptosis as part of the atresia process. In several types of cells, sphingosine-1-phospate (S1P) promotes cellular proliferation and survival, whereas ceramide (CER) triggers cell death, and the S1P/CER ratio may determine the fate of the cell. The aim of present study was to quantify S1P and CER concentrations and their ratio in bovine antral follicles of 8 to 17 mm classified as healthy and atretic antral follicles. Follicles were dissected from cow ovaries collected from a local abattoir. The theca cell layer, the granulosa cells and follicular fluid were separated, and 17β-estradiol (E2) and progesterone (P4) concentrations were measured in the follicular fluid by radioimmunoassay. Based on the E2/P4 ratio, the follicles were classified as healthy (2.2±0.3) or atretic (0.2±0.3). In both follicular compartments (granulosa and theca cell layer), sphingolipids were extracted and S1P and CER concentrations were quantified by HPLC (XTerra RP18; 5 µm, 3.0×150 mm column). Results showed that in both follicular compartments, S1P concentrations were higher in healthy antral follicles than in atretic antral follicles (P<0.05). The concentration of CER in the granulosa cells was higher in atretic antral follicles than in healthy antral follicles, but no differences were observed in the theca cell layer. The S1P/CER ratio in both follicular compartments was also higher in healthy antral follicles. Interestingly, in these follicles, there was a 45-fold greater concentration of S1P than CER in the granulosa cells (P<0.05), whereas in the theca cell layer, S1P had only a 14-fold greater concentration than CER when compared with atretic antral follicles. These results suggest that S1P plays a role in follicle health, increasing cellular proliferation and survival. In

  14. Uncleaved ApoM signal peptide is required for formation of large ApoM/sphingosine 1-phosphate (S1P)-enriched HDL particles.

    Liu, Mingxia; Allegood, Jeremy; Zhu, Xuewei; Seo, Jeongmin; Gebre, Abraham K; Boudyguina, Elena; Cheng, Dongmei; Chuang, Chia-Chi; Shelness, Gregory S; Spiegel, Sarah; Parks, John S

    2015-03-20

    Apolipoprotein M (apoM), a plasma sphingosine 1-phosphate (S1P) carrier, associates with plasma HDL via its uncleaved signal peptide. Hepatocyte-specific apoM overexpression in mice stimulates formation of both larger nascent HDL in hepatocytes and larger mature apoM/S1P-enriched HDL particles in plasma by enhancing hepatic S1P synthesis and secretion. Mutagenesis of apoM glutamine 22 to alanine (apoM(Q22A)) introduces a functional signal peptidase cleavage site. Expression of apoM(Q22A) in ABCA1-expressing HEK293 cells resulted in the formation of smaller nascent HDL particles compared with wild type apoM (apoM(WT)). When apoM(Q22A) was expressed in vivo, using recombinant adenoviruses, smaller plasma HDL particles and decreased plasma S1P and apoM were observed relative to expression of apoM(WT). Hepatocytes isolated from both apoM(WT)- and apoM(Q22A)-expressing mice displayed an equivalent increase in cellular levels of S1P, relative to LacZ controls; however, relative to apoM(WT), apoM(Q22A) hepatocytes displayed more rapid apoM and S1P secretion but minimal apoM(Q22A) bound to nascent lipoproteins. Pharmacologic inhibition of ceramide synthesis increased cellular sphingosine and S1P but not medium S1P in both apoM(WT) and apoM(Q22A) hepatocytes. We conclude that apoM secretion is rate-limiting for hepatocyte S1P secretion and that its uncleaved signal peptide delays apoM trafficking out of the cell, promoting formation of larger nascent apoM- and S1P-enriched HDL particles that are probably precursors of larger apoM/S1P-enriched plasma HDL. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Sphingosine-1-phosphate mediates proliferation maintaining the multipotency of human adult bone marrow and adipose tissue-derived stem cells.

    He, Xiaoli; H'ng, Shiau-Chen; Leong, David T; Hutmacher, Dietmar W; Melendez, Alirio J

    2010-08-01

    High renewal and maintenance of multipotency of human adult stem cells (hSCs), are a prerequisite for experimental analysis as well as for potential clinical usages. The most widely used strategy for hSC culture and proliferation is using serum. However, serum is poorly defined and has a considerable degree of inter-batch variation, which makes it difficult for large-scale mesenchymal stem cells (MSCs) expansion in homogeneous culture conditions. Moreover, it is often observed that cells grown in serum-containing media spontaneously differentiate into unknown and/or undesired phenotypes. Another way of maintaining hSC development is using cytokines and/or tissue-specific growth factors; this is a very expensive approach and can lead to early unwanted differentiation. In order to circumvent these issues, we investigated the role of sphingosine-1-phosphate (S1P), in the growth and multipotency maintenance of human bone marrow and adipose tissue-derived MSCs. We show that S1P induces growth, and in combination with reduced serum, or with the growth factors FGF and platelet-derived growth factor-AB, S1P has an enhancing effect on growth. We also show that the MSCs cultured in S1P-supplemented media are able to maintain their differentiation potential for at least as long as that for cells grown in the usual serum-containing media. This is shown by the ability of cells grown in S1P-containing media to be able to undergo osteogenic as well as adipogenic differentiation. This is of interest, since S1P is a relatively inexpensive natural product, which can be obtained in homogeneous high-purity batches: this will minimize costs and potentially reduce the unwanted side effects observed with serum. Taken together, S1P is able to induce proliferation while maintaining the multipotency of different human stem cells, suggesting a potential for S1P in developing serum-free or serum-reduced defined medium for adult stem cell cultures.

  16. Evaluation of plasma sphingosine 1-phosphate, hepcidin and cardiovascular damage biomarkers (cardiac troponin I and homocysteine) in rats infected with brucellosis and vaccinated (Rev-1, RB-51).

    Azimzadeh, Kaveh; Nasrollahi Nargesabad, Reza; Vousooghi, Nasim

    2017-08-01

    Brucellosis is known as one of important zoonosis. Studying the histological and biochemical effects of the disease could help to increase our knowledge about it. The aim of the present study was to evaluate changes of plasma parameters after intraperitoneal injection of two species of Brucella (Brucella melitensis and Brucella abortus) and two vaccines (Rev-1, RB-51) in the rat. Forty male rats were divided into five groups (n = 8 in each group). Two groups received suspensions of Brucella abortus and Brucella melitensis and two other groups were injected intraperitoneally with two mentioned vaccines and the last group received only distilled water. The results showed a significant increase in sphingosine 1-phosphate, Malondialdehyde, hepcidin, homocysteine, cardiac troponin I and copper levels and a considerable decrease in the levels of iron and zinc (P ≤ 0.01) in infected groups compared to the control animals. In vaccinated groups, hepcidin was increased but other parameters were not changed in comparison to the control group. It can be concluded that increase of homocysteine and cardiac troponin I in brucellosis could be a warning for cardiac adverse effects. Besides, increase of sphingosine 1-phosphate probably indicates its stimulant and modulatory effects in anti- Brucellosis biochemical pathways of the host. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Accurate quantification of sphingosine-1-phosphate in normal and Fabry disease plasma, cells and tissues by LC-MS/MS with (13)C-encoded natural S1P as internal standard

    Mirzaian, Mina; Wisse, Patrick; Ferraz, Maria J.; Marques, André R. A.; Gabriel, Tanit L.; van Roomen, Cindy P. A. A.; Ottenhoff, Roelof; van Eijk, Marco; Codée, Jeroen D. C.; van der Marel, Gijsbert A.; Overkleeft, Herman S.; Aerts, Johannes M.

    2016-01-01

    We developed a mass spectrometric procedure to quantify sphingosine-1-phosphate (S1P) in biological materials. The use of newly synthesized (13)C5 C18-S1P and commercial C17-S1P as internal standards rendered very similar results with respect to linearity, limit of detection and limit of

  18. Regulation of cellular sphingosine-1-phosphate by sphingosine kinase 1 and sphingosine-1-phopshate lyase determines chemotherapy resistance in gastroesophageal cancer

    Matula, Kasia; Collie-Duguid, Elaina; Murray, Graeme; Parikh, Khyati; Grabsch, Heike; Tan, Patrick; Lalwani, Salina; Garau, Roberta; Ong, Yuhan; Bain, Gillian; Smith, Asa-Dahle; Urquhart, Gordon; Bielawski, Jacek; Finnegan, Michael; Petty, Russell

    2015-01-01

    Resistance to chemotherapy is common in gastroesophageal cancer. Mechanisms of resistance are incompletely characterised and there are no predictive biomarkers in clinical practice for cytotoxic drugs. We used new cell line models to characterise novel chemotherapy resistance mechanisms and validated them in tumour specimens to identify new targets and biomarkers for gastroesophageal cancer. Cell lines were selected for resistance to oxaliplatin, cisplatin and docetaxel and gene expression examined using Affymetrix Exon 1.0 ST arrays. Leads were validated by qRT-PCR and HPLC of tumour metabolites. Protein expression and pharmacological inhibition of lead target SPHK1 was evaluated in independent cell lines, and by immunohistochemistry in gastroesophageal cancer patients. Genes with differential expression in drug resistant cell lines compared to the parental cell line they were derived from, were identified for each drug resistant cell line. Biological pathway analysis of these gene lists, identified over-represented pathways, and only 3 pathways - lysosome, sphingolipid metabolism and p53 signalling- were identified as over-represented in these lists for all three cytotoxic drugs investigated. The majority of genes differentially expressed in chemoresistant cell lines from these pathways, were involved in metabolism of glycosphingolipids and sphingolipids in lysosomal compartments suggesting that sphingolipids might be important mediators of cytotoxic drug resistance in gastroeosphageal cancers . On further investigation, we found that drug resistance (IC50) was correlated with increased sphingosine kinase 1(SPHK1) mRNA and also with decreased sphingosine-1-phosphate lysase 1(SGPL1) mRNA. SPHK1 and SGPL1 gene expression were inversely correlated. SPHK1:SGPL1 ratio correlated with increased cellular sphingosine-1-phosphate (S1P), and S1P correlated with drug resistance (IC50). High SPHK1 protein correlated with resistance to cisplatin (IC50) in an independent

  19. Identification of Chloride Channels CLCN3 and CLCN5 Mediating the Excitatory Cl− Currents Activated by Sphingosine-1-Phosphate in Sensory Neurons

    Qi, Yanmei; Mair, Norbert; Kummer, Kai K.; Leitner, Michael G.; Camprubí-Robles, María; Langeslag, Michiel; Kress, Michaela

    2018-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in numerous physiological and pathophysiological processes. We have previously reported a S1P-induced nocifensive response in mice by excitation of sensory neurons via activation of an excitatory chloride current. The underlying molecular mechanism for the S1P-induced chloride conductance remains elusive. In the present study, we identified two CLCN voltage-gated chloride channels, CLCN3 and CLCN5, which mediated a S1P-induced excitatory Cl− current in sensory neurons by combining RNA-seq, adenovirus-based gene silencing and whole-cell electrophysiological voltage-clamp recordings. Downregulation of CLCN3 and CLCN5 channels by adenovirus-mediated delivery of shRNA dramatically reduced S1P-induced Cl− current and membrane depolarization in sensory neurons. The mechanism of S1P-induced activation of the chloride current involved Rho GTPase but not Rho-associated protein kinase. Although S1P-induced potentiation of TRPV1-mediated ionic currents also involved Rho-dependent process, the lack of correlation of the S1P-activated Cl− current and the potentiation of TRPV1 by S1P suggests that CLCN3 and CLCN5 are necessary components for S1P-induced excitatory Cl− currents but not for the amplification of TRPV1-mediated currents in sensory neurons. This study provides a novel mechanistic insight into the importance of bioactive sphingolipids in nociception. PMID:29479306

  20. Identification of Chloride Channels CLCN3 and CLCN5 Mediating the Excitatory Cl− Currents Activated by Sphingosine-1-Phosphate in Sensory Neurons

    Yanmei Qi

    2018-02-01

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive sphingolipid involved in numerous physiological and pathophysiological processes. We have previously reported a S1P-induced nocifensive response in mice by excitation of sensory neurons via activation of an excitatory chloride current. The underlying molecular mechanism for the S1P-induced chloride conductance remains elusive. In the present study, we identified two CLCN voltage-gated chloride channels, CLCN3 and CLCN5, which mediated a S1P-induced excitatory Cl− current in sensory neurons by combining RNA-seq, adenovirus-based gene silencing and whole-cell electrophysiological voltage-clamp recordings. Downregulation of CLCN3 and CLCN5 channels by adenovirus-mediated delivery of shRNA dramatically reduced S1P-induced Cl− current and membrane depolarization in sensory neurons. The mechanism of S1P-induced activation of the chloride current involved Rho GTPase but not Rho-associated protein kinase. Although S1P-induced potentiation of TRPV1-mediated ionic currents also involved Rho-dependent process, the lack of correlation of the S1P-activated Cl− current and the potentiation of TRPV1 by S1P suggests that CLCN3 and CLCN5 are necessary components for S1P-induced excitatory Cl− currents but not for the amplification of TRPV1-mediated currents in sensory neurons. This study provides a novel mechanistic insight into the importance of bioactive sphingolipids in nociception.

  1. Sphingosine 1-phosphate stimulates hydrogen peroxide generation through activation of phospholipase C-Ca2+ system in FRTL-5 thyroid cells: possible involvement of guanosine triphosphate-binding proteins in the lipid signaling.

    Okajima, F; Tomura, H; Sho, K; Kimura, T; Sato, K; Im, D S; Akbar, M; Kondo, Y

    1997-01-01

    Exogenous sphingosine 1-phosphate (S1P) stimulated hydrogen peroxide (H2O2) generation in association with an increase in intracellular Ca2+ concentration in FRTL-5 thyroid cells. S1P also induced inositol phosphate production, reflecting activation of phospholipase C (PLC) in the cells. These three S1P-induced events were inhibited partially by pertussis toxin (PTX) and markedly by U73122, a PLC inhibitor, and were conversely potentiated by N6-(L-2-phenylisopropyl)adenosine, an A1-adenosine receptor agonist. In FRTL-5 cell membranes, S1P also activated PLC in the presence of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), but not in its absence. Guanosine 5'-O-(2-thiodiphosphate) inhibited the S1P-induced GTP gamma S-dependent activation of the enzyme. To characterize the signaling pathways, especially receptors and G proteins involved in the S1P-induced responses, cross-desensitization experiments were performed. Under the conditions where homologous desensitization occurred in S1P-, lysophosphatidic acid (LPA)-, and bradykinin-induced induction of Ca2+ mobilization, no detectable cross-desensitization of S1P and bradykinin was observed. This suggests that the primary action of S1P in its activation of the PLC-Ca2+ system was not the activation of G proteins common to S1P and bradykinin, but the activation of a putative S1P receptor. On the other hand, there was a significant cross-desensitization of S1P and LPA; however, a still significant response to S1P (50-80% of the response in the nontreated control cells) was observed depending on the lipid dose employed after a prior LPA challenge. S1P also inhibited cAMP accumulation in a PTX-sensitive manner. We conclude that S1P stimulates H2O2 generation through a PLC-Ca2+ system and also inhibits adenylyl cyclase in FRTL-5 thyroid cells. The S1P-induced responses may be mediated partly through a putative lipid receptor that is coupled to both PTX-sensitive and insensitive G proteins.

  2. Sphingosine-1-phosphate suppresses chondrosarcoma metastasis by upregulation of tissue inhibitor of metalloproteinase 3 through suppressing miR-101 expression.

    Tsai, Chun-Hao; Yang, Dong-Ying; Lin, Chih-Yang; Chen, Tsung-Ming; Tang, Chih-Hsin; Huang, Yuan-Li

    2017-10-01

    Chondrosarcoma is the second most common primary malignancy form of bone cancer, exhibiting resistance to chemotherapy and radiation therapy as well as developing high metastasis ability in late-stage tumors. Thus, understanding the metastatic processes of chondrosarcoma is considered a strategy for the treatment of this disease. Sphingosine 1-phosphate (S1P), a bioactive sphingolipid, is produced intracellularly by sphingosine kinase (SphK) and is regarded as a second signaling molecule that regulates inflammation, proliferation, angiogenesis, and metastasis. However, the effect of S1P on chondrosarcoma remains uncertain. As demonstrated by the transwell, immunoblotting, and real-time PCR analyses, we found that S1P inhibited cell migration and MMP-2 expression through the upregulation of the tissue inhibitor of metalloproteinase-3 (TIMP-3) expression in human chondrosarcoma cells. Additionally, we also showed that microRNA (miRNA)-101, which targets the 3' untranslated region (3'UTR) of TIMP-3, decreased significantly following S1P treatment. After transfection with miR-101 mimics, the S1P-regulated cell migration and TIMP-3 expression were both reversed. Furthermore, we also showed that the S1P-inhibited cell migration is mediated through the c-Src/MEK/ERK signaling axis. Meanwhile, the in vivo study indicated that overexpression of SphK1 decreases chondrosarcoma metastasis to the lungs. Our results illustrate the clinical significance between SphK1, TIMP-3, and miR-101 in human chondrosarcoma patients. Taken together, our results suggest that S1P and miR-101 may prove to be potential therapeutic targets for future chondrosarcoma treatment. © 2017 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.

  3. The relationship between the high-density lipoprotein (HDL)-associated sphingosine-1-phosphate (S1P) and coronary in-stent restenosis.

    Jing, Xiao-Dong; Wei, Xiao-Ming; Deng, Song-Bai; Du, Jian-Lin; Liu, Ya-Jie; She, Qiang

    2015-06-15

    High-density lipoprotein (HDL)-associated sphingosine-1-phosphate (S1P) contributed to several beneficial effects in the cardiovascular system. We explored the relationship between the HDL-S1P concentrations and coronary in-stent restenosis (ISR). Fifty consecutive patients with ISR and 50 normal control subjects were included. The serum S1P, HDL-S1P and clinical data were collected to explore the relationships between these parameters and ISR. The patients with ISR had significantly lower concentrations of serum S1P (96.10 ± 26.33 vs. 113.40 ± 32.72; P = 0.004) and HDL-S1P (32.81 ± 10.02 vs. 42.72 ± 11.75; P S1P: Quartile 1 (18.63-28.51 ng/ml), Quartile 2 (28.62-37.28 ng/ml), Quartile 3 (37.35-45.27 ng/ml), and Quartile 4 (45.59-79.36 ng/ml). The rates of ISR were 84%, 48%, 40% and 28%, respectively. The patients in Quartile 1 exhibited significantly higher rates of ISR compared with the other groups (P = 0.001). A multivariate stepwise logistic regression analysis indicated that HDL-S1P (OR = 0.846, 95% CI = 0.767-0.932, P = 0.001) was an independent predictor of ISR. An ROC analysis indicated that HDL-S1P = 30.37 ng/ml and had a 90% sensitivity and a 52% specificity in predicting ISR. HDL-S1P is an independent predictor of ISR, and patients with higher concentrations of HDL-S1P have a low risk of ISR. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Modulation of sphingosine 1-phosphate (S1P) attenuates spatial learning and memory impairments in the valproic acid rat model of autism.

    Wu, Hongmei; Zhang, Quanzhi; Gao, Jingquan; Sun, Caihong; Wang, Jia; Xia, Wei; Cao, Yonggang; Hao, Yanqiu; Wu, Lijie

    2018-03-01

    Autism spectrum disorders (ASD) are a set of pervasive neurodevelopmental disorders that manifest in early childhood, and it is growing up to be a major cause of disability in children. However, the etiology and treatment of ASD are not well understood. In our previous study, we found that serum levels of sphingosine 1-phosphate (S1P) were increased significantly in children with autism, indicating that S1P levels may be involved in ASD. The objective of this study was to identify a link between increased levels of S1P and neurobehavioral changes in autism. We utilized a valproic acid (VPA) -induced rat model of autism to evaluate the levels of S1P and the expression of sphingosine kinase (SphK), a key enzyme for S1P production, in serum and hippocampal tissue. Furthermore, we assessed cognitive functional changes and histopathological and neurochemical alterations in VPA-exposed rats after SphK blockade to explore the possible link between increased levels of S1P and neurobehavioral changes in autism. We found that SphK2 and S1P are upregulated in hippocampal tissue from VPA-exposed rats, while pharmacological inhibition of SphK reduced S1P levels, attenuated spatial learning and memory impairments, increased the expression of phosphorylated CaMKII and CREB and autophagy-related proteins, inhibited cytochrome c release, decreased the expression of apoptosis related proteins, and protected against neuronal loss in the hippocampus. We have demonstrated that an increased level of SphK2/S1P is involved in the spatial learning and memory impairments of autism, and this signaling pathway represents a novel therapeutic target and direction for future studies.

  5. Sphingosine-1-Phosphate (S1P) Impacts Presynaptic Functions by Regulating Synapsin I Localization in the Presynaptic Compartment.

    Riganti, Loredana; Antonucci, Flavia; Gabrielli, Martina; Prada, Ilaria; Giussani, Paola; Viani, Paola; Valtorta, Flavia; Menna, Elisabetta; Matteoli, Michela; Verderio, Claudia

    2016-04-20

    Growing evidence indicates that sphingosine-1-P (S1P) upregulates glutamate secretion in hippocampal neurons. However, the molecular mechanisms through which S1P enhances excitatory activity remain largely undefined. The aim of this study was to identify presynaptic targets of S1P action controlling exocytosis. Confocal analysis of rat hippocampal neurons showed that S1P applied at nanomolar concentration alters the distribution of Synapsin I (SynI), a presynaptic phosphoprotein that controls the availability of synaptic vesicles for exocytosis. S1P induced SynI relocation to extrasynaptic regions of mature neurons, as well as SynI dispersion from synaptic vesicle clusters present at axonal growth cones of developing neurons. S1P-induced SynI relocation occurred in a Ca(2+)-independent but ERK-dependent manner, likely through the activation of S1P3 receptors, as it was prevented by the S1P3 receptor selective antagonist CAY1044 and in neurons in which S1P3 receptor was silenced. Our recent evidence indicates that microvesicles (MVs) released by microglia enhance the metabolism of endogenous sphingolipids in neurons and stimulate excitatory transmission. We therefore investigated whether MVs affect SynI distribution and whether endogenous S1P could be involved in the process. Analysis of SynI immunoreactivity showed that exposure to microglial MVs induces SynI mobilization at presynaptic sites and growth cones, whereas the use of inhibitors of sphingolipid cascade identified S1P as the sphingolipid mediating SynI redistribution. Our data represent the first demonstration that S1P induces SynI mobilization from synapses, thereby indicating the phosphoprotein as a novel target through which S1P controls exocytosis. Growing evidence indicates that the bioactive lipid sphingosine and its metabolite sphingosine-1-P (S1P) stimulate excitatory transmission. While it has been recently clarified that sphingosine influences directly the exocytotic machinery by activating the

  6. Sphingosine-1-Phosphate Mediates ICAM-1-Dependent Monocyte Adhesion through p38 MAPK and p42/p44 MAPK-Dependent Akt Activation

    Lin, Chih-Chung; Lee, I-Ta; Hsu, Chun-Hao; Hsu, Chih-Kai; Chi, Pei-Ling; Hsiao, Li-Der; Yang, Chuen-Mao

    2015-01-01

    Up-regulation of intercellular adhesion molecule-1 (ICAM-1) is frequently implicated in lung inflammation. Sphingosine-1-phosphate (S1P) has been shown to play a key role in inflammation via adhesion molecules induction, and then causes lung injury. However, the mechanisms underlying S1P-induced ICAM-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain unclear. The effect of S1P on ICAM-1 expression was determined by Western blot and real-time PCR. The involvement of signaling pathways in these responses was investigated by using the selective pharmacological inhibitors and transfection with siRNAs. S1P markedly induced ICAM-1 expression and monocyte adhesion which were attenuated by pretreatment with the inhibitor of S1PR1 (W123), S1PR3 (CAY10444), c-Src (PP1), EGFR (AG1478), PDGFR (AG1296), MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), PI3K (LY294002), or AP-1 (Tanshinone IIA) and transfection with siRNA of S1PR1, S1PR3, c-Src, EGFR, PDGFR, p38, p42, JNK1, c-Jun, or c-Fos. We observed that S1P-stimulated p42/p44 MAPK and p38 MAPK activation was mediated via a c-Src/EGFR and PDGFR-dependent pathway. S1P caused the c-Src/EGFR/PDGFR complex formation. On the other hand, we demonstrated that S1P induced p42/p44 MAPK and p38 MAPK-dependent Akt activation. In addition, S1P-stimulated JNK1/2 phosphorylation was attenuated by SP600125 or PP1. Finally, S1P enhanced c-Fos mRNA levels and c-Jun phosphorylation. S1P-induced c-Jun activation was reduced by PP1, AG1478, AG1296, U0126, SP600125, SB202190, or LY294002. These results demonstrated that S1P-induced ICAM-1 expression and monocyte adhesion were mediated through S1PR1/3/c-Src/EGFR, PDGFR/p38 MAPK, p42/p44 MAPK/Akt-dependent AP-1 activation. PMID:25734900

  7. Crystal Structure of a Lipid G Protein-Coupled Receptor

    Hanson, Michael A; Roth, Christopher B; Jo, Euijung; Griffith, Mark T; Scott, Fiona L; Reinhart, Greg; Desale, Hans; Clemons, Bryan; Cahalan, Stuart M; Schuerer, Stephan C; Sanna, M Germana; Han, Gye Won; Kuhn, Peter; Rosen, Hugh; Stevens, Raymond C [Scripps; (Receptos)

    2012-03-01

    The lyso-phospholipid sphingosine 1-phosphate modulates lymphocyte trafficking, endothelial development and integrity, heart rate, and vascular tone and maturation by activating G protein-coupled sphingosine 1-phosphate receptors. Here, we present the crystal structure of the sphingosine 1-phosphate receptor 1 fused to T4-lysozyme (S1P1-T4L) in complex with an antagonist sphingolipid mimic. Extracellular access to the binding pocket is occluded by the amino terminus and extracellular loops of the receptor. Access is gained by ligands entering laterally between helices I and VII within the transmembrane region of the receptor. This structure, along with mutagenesis, agonist structure-activity relationship data, and modeling, provides a detailed view of the molecular recognition and requirement for hydrophobic volume that activates S1P1, resulting in the modulation of immune and stromal cell responses.

  8. miR-125b-1-3p inhibits trophoblast cell invasion by targeting sphingosine-1-phosphate receptor 1 in preeclampsia.

    Li, Qinghua; Pan, Zhifang; Wang, Xuejian; Gao, Zhiqin; Ren, Chune; Yang, Weiwei

    2014-10-10

    Preeclampsia (PE) is the leading cause of maternal and perinatal mortality and morbidity. Understanding the molecular mechanisms underlying placentation facilitates the development of better intervention of this disease. MicroRNAs are strongly implicated in the pathogenesis of this syndrome. In current study, we found that miR-125b-1-3p was elevated in placentas derived from preeclampsia patients. Transfection of miR-125b-1-3p mimics significantly inhibited the invasiveness of human trophoblast cells, whereas miR-125b-1-3p inhibitor enhanced trophoblast cell invasion. Luciferase assays identified that S1PR1 was a novel direct target of miR-125b-1-3p in the placenta. Overexpression of S1PR1 could reverse the inhibitory effect of miR-125b-1-3p on the invasion of trophoblast cells. These findings suggested that abnormal expression of miR-125b-1-3p might contribute to the pathogenesis of preeclampsia. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Sphingosine 1 Phosphate (S1P) Receptors 1 and 2 Coordinately Induce Osteoblast Migration Through S1P Activation of Complementary Kinase Pathways

    Quint, Patrick; Ruan, Ming; Pederson, Larry

    2013-01-01

    Normal bone turnover requires tight coupling of bone resorption and bone formation to preserve bone quantity and structure. With aging and during several pathological conditions, this coupling breaks down, leading to either net bone loss or excess bone formation. To preserve or restore normal bon...

  10. Accurate quantification of sphingosine-1-phosphate in normal and Fabry disease plasma, cells and tissues by LC-MS/MS with (13)C-encoded natural S1P as internal standard.

    Mirzaian, Mina; Wisse, Patrick; Ferraz, Maria J; Marques, André R A; Gabriel, Tanit L; van Roomen, Cindy P A A; Ottenhoff, Roelof; van Eijk, Marco; Codée, Jeroen D C; van der Marel, Gijsbert A; Overkleeft, Herman S; Aerts, Johannes M

    2016-08-01

    We developed a mass spectrometric procedure to quantify sphingosine-1-phosphate (S1P) in biological materials. The use of newly synthesized (13)C5 C18-S1P and commercial C17-S1P as internal standards rendered very similar results with respect to linearity, limit of detection and limit of quantitation. Caution is warranted with determination of plasma S1P levels. Earlier it was reported that S1P is elevated in plasma of Fabry disease patients. We investigated this with the improved quantification. No clear conclusion could be drawn for patient plasma samples given the lack of uniformity of blood collection and plasma preparation. To still obtain insight, plasma and tissues were identically collected from α-galactosidase A deficient Fabry mice and matched control animals. No significant difference was observed in plasma S1P levels. A significant 2.3 fold increase was observed in kidney of Fabry mice, but not in liver and heart. Comparative analysis of S1P in cultured fibroblasts from normal subjects and classically affected Fabry disease males revealed no significant difference. In conclusion, accurate quantification of S1P in biological materials is feasible by mass spectrometry using the internal standards (13)C5 C18-S1P or C17-S1P. Significant local increases of S1P in the kidney might occur in Fabry disease as suggested by the mouse model. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Sphingosine-1-phosphate promotes extravillous trophoblast cell invasion by activating MEK/ERK/MMP-2 signaling pathways via S1P/S1PR1 axis activation.

    Yang, Weiwei; Li, Qinghua; Pan, Zhifang

    2014-01-01

    Successful placentation depends on the proper invasion of extravillous trophoblast (EVT) cells into maternal tissues. Previous reports demonstrated that S1P receptors are expressed in the EVT cells and S1P could regulate migration and function of trophoblast cells via S1P receptors. However, little is known about roles of S1P in the invasion of EVT cells. Our study was performed to investigate S1P effect on the invasion of EVT cells. We used the extravillous trophoblast cell line HTR8/SVneo cells to evaluate the effect. In vitro invasion assay was employed to determine the invasion of HTR8/SVneo cells induced by S1P. MMP-2 enzyme activity and relative level in the supernatants of HTR8/SVneo was assessed by gelatin zymography and western blot. Based on the above, siRNA and specific inhibitors were used for the intervention and study of potential signal pathways, and Real-time qPCR and western blot were used to test the mRNA and protein level of potential signal targets. We found that S1P could promote HTR8/SVneo cell invasion and upregulates activity and level of MMP-2. The promotion requires activation of MEK-ERK and is dependent on the axis of S1P/S1PR1. Our investigation of S1P may provide new insights into the molecular mechanisms of EVT invasion.

  12. Sphingosine-1-Phosphate (S1P) Is a Feasible Biomarker in Predicting the Efficacy of Polymyxin B-Immobilized Fiber Direct Hemoperfusion (PMX-DHP) in Patients with Septic Shock.

    Inoue, Satoshi; Sakamoto, Yuichiro; Koami, Hiroyuki; Yamada C, Kosuke; Nagashima, Futoshi; Miike, Toru; Iwamura, Takashi; Obata, Toru

    2018-01-01

    The aim of this study was to identify a useful biomarker to predict the efficacy of polymyxin B-immobilized fiber direct hemoperfusion (PMX-DHP) in patients with septic shock. The 44 patients included in this study were divided into two groups. Group A had an increase in systolic blood pressure (SBP) over 30 mmHg after PMX-DHP treatment. Group B had an increase in SBP less than 30 mmHg after PMX-DHP treatment. We evaluated the clinical characteristics and demographics of both groups. We also assessed whether the cause of sepsis affected the efficacy of PMX-DHP and compared the prognosis of both groups. Finally, we investigated whether there were any significant differences in the levels of sepsis-related biomarkers, including sphingosine-1-phosphate (S1P), between both groups before PMX-DHP in an effort to identify a biomarker that could predict the efficacy of PMX-DHP. PMX-DHP significantly increased SBP regardless of the cause of sepsis. Although there was some tendency, PMX-DHP did not significantly improve the prognosis of effective cases in comparison with non-effective cases, probably because of the limited number of patients included. Among the sepsis-related biomarkers, only S1P values were significantly different between the two groups before PMX-DHP, and S1P levels were significantly increased after treatment in the effective cases. S1P levels prior to PMX-DHP can be used to predict its efficacy. In addition, continuous monitoring of S1P levels can indicate the effectiveness of PMX-DHP in patients with septic shock.

  13. Sphingosine kinase 1 is regulated by peroxisome proliferator-activated receptor α in response to free fatty acids and is essential for skeletal muscle interleukin-6 production and signaling in diet-induced obesity.

    Ross, Jessica S; Hu, Wei; Rosen, Bess; Snider, Ashley J; Obeid, Lina M; Cowart, L Ashley

    2013-08-02

    We previously demonstrated that sphingosine kinase 1 (Sphk1) expression and activity are up-regulated by exogenous palmitate (PAL) in a skeletal muscle model system and in diet-induced obesity in mice; however, potential functions and in vivo relevance of this have not been addressed. Here, we aimed to determine the mechanism by which PAL regulates SphK1 in muscle, and to determine potential roles for its product, sphingosine-1-phosphate (S1P), in muscle biology in the context of obesity. Cloning and analysis of the mouse Sphk1 promoter revealed a peroxisome proliferator-activated receptor (PPAR) α cis-element that mediated activation of a reporter under control of the Sphk1 promoter; direct interaction of PPARα was demonstrated by chromatin immunoprecipitation. PAL treatment induced the proinflammatory cytokine interleukin (IL)-6 in a manner dependent on SphK1, and this was attenuated by inhibition of the sphingosine-1-phosphate receptor 3 (S1PR3). Diet-induced obesity in mice demonstrated that IL-6 expression in muscle, but not adipose tissue, increased in obesity, but this was attenuated in Sphk1(-/-) mice. Moreover, plasma IL-6 levels were significantly decreased in obese Sphk1(-/-) mice relative to obese wild type mice, and muscle, but not adipose tissue IL-6 signaling was activated. These data indicate that PPARα regulates Sphk1 expression in the context of fatty acid oversupply and links PAL to muscle IL-6 production. Moreover, this function of SphK1 in diet-induced obesity suggests a potential role for SphK1 in obesity-associated pathological outcomes.

  14. Co-ordinate regulation of growth factor receptors and lipid phosphate phosphatase-1 controls cell activation by exogenous lysophosphatidate.

    Pilquil, C; Ling, Z C; Singh, I; Buri, K; Zhang, Q X; Brindley, D N

    2001-11-01

    The serum-derived lipid growth factors, lysophosphatidate (LPA) and sphingosine 1-phosphate (S1P), activate cells selectively through different members of a family of endothelial differentiation gene (EDG) receptors. Activation of EDG receptors by LPA and S1P provides a variety of signalling cascades depending upon the G-protein coupling of the different EDG receptors. This leads to chemotactic and mitogenic responses, which are important in wound healing. For example, LPA stimulates fibroblast division and S1P stimulates the chemotaxis and division of endothelial cells leading to angiogenesis. Counteracting these effects of LPA and S1P, are the actions of lipid phosphate phosphatases (LPP, or phosphatidate phosphohydrolases, Type 2). The isoform LPP-1 is expressed in the plasma membrane with its active site outside the cell. This enzyme is responsible for 'ecto-phosphatase' activity leading to the degradation of exogenous lipid phosphate mediators, particularly LPA. Expression of LPP-1 decreases cell activation by exogenous LPA. The mechanism for this is controversial and several mechanisms have been proposed. Evidence will be presented that the LPPs cross-talk with EDG and other growth factor receptors, thus, regulating the responses of the cells to lipid phosphate mediators of signal transduction.

  15. Lysophospholipid Receptors Are Differentially Expressed in Rat Terminal Schwann Cells, As Revealed by a Single Cell RT-PCR and In Situ Hybridization

    Kobashi, Hiroaki; Yaoi, Takeshi; Oda, Ryo; Okajima, Seiichiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Fushiki, Shinji

    2006-01-01

    Terminal Schwann cells (TSCs) that cover motor neuron terminals, are known to play an important role in maintaining neuromuscular junctions, as well as in the repair process after nerve injury. However, the molecular characteristics of TSCs remain unknown, because of the difficulties in analyzing them due to their paucity. By using our previously reported method of selectively and efficiently collecting TSCs, we have analyzed the difference in expression patterns of lysophospholipid (LPL) receptor genes (LPA 1 , LPA 2 , LPA 3 , S1P 1 , S1P 2 , S1P 3 , S1P 4 , and S1P 5 ) between TSCs and myelinating Schwann cells (MSCs). LPL, which includes lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), is the bioactive lipid that induces a myriad of cellular responses through specific members of G-protein coupled receptors for LPA. It turned out that LPA 3 was expressed only in TSCs, whereas S1P 1 was expressed in TSCs and skeletal muscle, but not in MSCs. Other types of LPL receptor genes, including LPA 1 , S1P 2 , S1P 3 , S1P 4 , were expressed in both types of Schwann cells. None of the LPL receptor gene family showed MSCs-specific expression

  16. Plasma sphingosine-1-phosphate is elevated in obesity.

    Greg M Kowalski

    Full Text Available BACKGROUND: Dysfunctional lipid metabolism is a hallmark of obesity and insulin resistance and a risk factor for various cardiovascular and metabolic complications. In addition to the well known increase in plasma triglycerides and free fatty acids, recent work in humans and rodents has shown that obesity is associated with elevations in the bioactive class of sphingolipids known as ceramides. However, in obesity little is known about the plasma concentrations of sphinogsine-1-phosphate (S1P, the breakdown product of ceramide, which is an important signaling molecule in mammalian biology. Therefore, the purpose of this study was to examine the impact of obesity on circulating S1P concentration and its relationship with markers of glucose metabolism and insulin sensitivity. METHODOLOGY/PRINCIPAL FINDINGS: Plasma S1P levels were determined in high-fat diet (HFD-induced and genetically obese (ob/ob mice along with obese humans. Circulating S1P was elevated in both obese mouse models and in obese humans compared with lean healthy controls. Furthermore, in humans, plasma S1P positively correlated with total body fat percentage, body mass index (BMI, waist circumference, fasting insulin, HOMA-IR, HbA1c (%, total and LDL cholesterol. In addition, fasting increased plasma S1P levels in lean healthy mice. CONCLUSION: We show that elevations in plasma S1P are a feature of both human and rodent obesity and correlate with metabolic abnormalities such as adiposity and insulin resistance.

  17. The apolipoprotein m-sphingosine-1-phosphate axis

    Arkensteijn, Bas W C; Berbée, Jimmy F P; Rensen, Patrick C N

    2013-01-01

    Apolipoprotein M (apoM) is a plasma apolipoprotein that mainly associates with high-density lipoproteins. Hence, most studies on apoM so far have investigated its effect on and association with lipid metabolism and atherosclerosis. The insight into apoM biology recently took a major turn. Apo...

  18. The promotion of mandibular defect healing by the targeting of S1P receptors and the recruitment of alternatively activated macrophages.

    Das, Anusuya; Segar, Claire E; Hughley, Brian B; Bowers, Daniel T; Botchwey, Edward A

    2013-12-01

    Endogenous signals originating at the site of injury are involved in the paracrine recruitment, proliferation, and differentiation of circulating progenitor and diverse inflammatory cell types. Here, we investigate a strategy to exploit endogenous cell recruitment mechanisms to regenerate injured bone by local targeting and activation of sphingosine-1-phosphate (S1P) receptors. A mandibular defect model was selected for evaluating regeneration of bone following trauma or congenital disease. The particular challenges of mandibular reconstruction are inherent in the complex anatomy and function of the bone given that the area is highly vascularized and in close proximity to muscle. Nanofibers composed of poly(DL-lactide-co-glycolide) (PLAGA) and polycaprolactone (PCL) were used to delivery FTY720, a targeted agonist of S1P receptors 1 and 3. In vitro culture of bone progenitor cells on drug-loaded constructs significantly enhanced SDF1α mediated chemotaxis of bone marrow mononuclear cells. In vivo results show that local delivery of FTY720 from composite nanofibers enhanced blood vessel ingrowth and increased recruitment of M2 alternatively activated macrophages, leading to significant osseous tissue ingrowth into critical sized defects after 12 weeks of treatment. These results demonstrate that local activation of S1P receptors is a regenerative cue resulting in recruitment of wound healing or anti-inflammatory macrophages and bone healing. Use of such small molecule therapy can provide an alternative to biological factors for the clinical treatment of critical size craniofacial defects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. α1B-Adrenergic Receptors Differentially Associate with Rab Proteins during Homologous and Heterologous Desensitization

    Castillo-Badillo, Jean A.; Sánchez-Reyes, Omar B.; Alfonzo-Méndez, Marco A.; Romero-Ávila, M. Teresa; Reyes-Cruz, Guadalupe; García-Sáinz, J. Adolfo

    2015-01-01

    Internalization of G protein-coupled receptors can be triggered by agonists or by other stimuli. The process begins within seconds of cell activation and contributes to receptor desensitization. The Rab GTPase family controls endocytosis, vesicular trafficking, and endosomal fusion. Among their remarkable properties is the differential distribution of its members on the surface of various organelles. In the endocytic pathway, Rab 5 controls traffic from the plasma membrane to early endosomes, whereas Rab 4 and Rab 11 regulate rapid and slow recycling from early endosomes to the plasma membrane, respectively. Moreover, Rab 7 and Rab 9 regulate the traffic from late endosomes to lysosomes and recycling to the trans-Golgi. We explore the possibility that α1B-adrenergic receptor internalization induced by agonists (homologous) and by unrelated stimuli (heterologous) could involve different Rab proteins. This possibility was explored by Fluorescence Resonance Energy Transfer (FRET) using cells coexpressing α1B-adrenergic receptors tagged with the red fluorescent protein, DsRed, and different Rab proteins tagged with the green fluorescent protein. It was observed that when α1B-adrenergic receptors were stimulated with noradrenaline, the receptors interacted with proteins present in early endosomes, such as the early endosomes antigen 1, Rab 5, Rab 4, and Rab 11 but not with late endosome markers, such as Rab 9 and Rab 7. In contrast, sphingosine 1-phosphate stimulation induced rapid and transient α1B-adrenergic receptor interaction of relatively small magnitude with Rab 5 and a more pronounced and sustained one with Rab 9; interaction was also observed with Rab 7. Moreover, the GTPase activity of the Rab proteins appears to be required because no FRET was observed when dominant-negative Rab mutants were employed. These data indicate that α1B-adrenergic receptors are directed to different endocytic vesicles depending on the desensitization type (homologous vs

  20. The activation of RhoC in vascular endothelial cells is required for the S1P receptor type 2-induced inhibition of angiogenesis.

    Del Galdo, Sabrina; Vettel, Christiane; Heringdorf, Dagmar Meyer Zu; Wieland, Thomas

    2013-12-01

    Sphingosine-1-phosphate (S1P) is a multifunctional phospholipid inducing a variety of cellular responses in endothelial cells (EC). S1P responses are mediated by five G protein coupled receptors of which three types (S1P1R-S1P3R) have been described to be of importance in vascular endothelial cells (EC). Whereas the S1P1R regulates endothelial barrier function by coupling to Gαi and the monomeric GTPase Rac1, the signaling pathways involved in the S1P-induced regulation of angiogenesis are ill defined. We therefore studied the sprouting of human umbilical vein EC (HUVEC) in vitro and analyzed the activation of the RhoGTPases RhoA and RhoC. Physiological relevant concentrations of S1P (100-300nM) induce a moderate activation of RhoA and RhoC. Inhibition or siRNA-mediated depletion of the S1P2R preferentially decreased the activation of RhoC. Both manipulations caused an increase of sprouting in a spheroid based in vitro sprouting assay. Interestingly, a similar increase in sprouting was detected after effective siRNA-mediated knockdown of RhoC. In contrast, the depletion of RhoA had no influence on sprouting. Furthermore, suppression of the activity of G proteins of the Gα12/13 subfamily by adenoviral overexpression of the regulator of G protein signaling domain of LSC as well as siRNA-mediated knockdown of the Rho specific guanine nucleotide exchange factor leukemia associated RhoGEF (LARG) inhibited the S1P-induced activation of RhoC and concomitantly increased sprouting of HUVEC with similar efficacy. We conclude that the angiogenic sprouting of EC is suppressed via the S1P2R subtype. Thus, the increase in basal sprouting can be attributed to blocking of the inhibitory action of autocrine S1P stimulating the S1P2R. This inhibitory pathway involves the activation of RhoC via Gα12/13 and LARG, while the simultaneously occurring activation of RhoA is apparently dispensable here. © 2013.

  1. Blocking S1P interaction with S1P1 receptor by a novel competitive S1P1-selective antagonist inhibits angiogenesis

    Fujii, Yasuyuki; Ueda, Yasuji; Ohtake, Hidenori; Ono, Naoya; Takayama, Tetsuo; Nakazawa, Kiyoshi; Igarashi, Yasuyuki; Goitsuka, Ryo

    2012-01-01

    Highlights: ► The effect of a newly developed S1P 1 -selective antagonist on angiogenic responses. ► S1P 1 is a critical component of VEGF-related angiogenic responses. ► S1P 1 -selective antagonist showed in vitro activity to inhibit angiogenesis. ► S1P 1 -selective antagonist showed in vivo activity to inhibit angiogenesis. ► The efficacy of S1P 1 -selective antagonist for anti-cancer therapies. -- Abstract: Sphingosine 1-phosphate receptor type 1 (S1P 1 ) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P 1 and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P 1 -selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P 1 antagonists. TASP0277308 inhibited S1P- as well as VEGF-induced cellular responses, including migration and proliferation of human umbilical vein endothelial cells. Furthermore, TASP0277308 effectively blocked a VEGF-induced tube formation in vitro and significantly suppressed tumor cell-induced angiogenesis in vivo. These findings revealed that S1P 1 is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

  2. Selective coupling of the S1P3 receptor subtype to S1P-mediated RhoA activation and cardioprotection.

    Yung, Bryan S; Brand, Cameron S; Xiang, Sunny Y; Gray, Charles B B; Means, Christopher K; Rosen, Hugh; Chun, Jerold; Purcell, Nicole H; Brown, Joan Heller; Miyamoto, Shigeki

    2017-02-01

    Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid, is generated and released at sites of tissue injury in the heart and can act on S1P 1 , S1P 2 , and S1P 3 receptor subtypes to affect cardiovascular responses. We established that S1P causes little phosphoinositide hydrolysis and does not induce hypertrophy indicating that it does not cause receptor coupling to G q . We previously demonstrated that S1P confers cardioprotection against ischemia/reperfusion by activating RhoA and its downstream effector PKD. The S1P receptor subtypes and G proteins that regulate RhoA activation and downstream responses in the heart have not been determined. Using siRNA or pertussis toxin to inhibit different G proteins in NRVMs we established that S1P regulates RhoA activation through Gα 13 but not Gα 12 , Gα q , or Gα i . Knockdown of the three major S1P receptors using siRNA demonstrated a requirement for S1P 3 in RhoA activation and subsequent phosphorylation of PKD, and this was confirmed in studies using isolated hearts from S1P 3 knockout (KO) mice. S1P treatment reduced infarct size induced by ischemia/reperfusion in Langendorff perfused wild-type (WT) hearts and this protection was abolished in the S1P 3 KO mouse heart. CYM-51736, an S1P 3 -specific agonist, also decreased infarct size after ischemia/reperfusion to a degree similar to that achieved by S1P. The finding that S1P 3 receptor- and Gα 13 -mediated RhoA activation is responsible for protection against ischemia/reperfusion suggests that selective targeting of S1P 3 receptors could provide therapeutic benefits in ischemic heart disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Lysophospholipid Growth Factors and Their G Protein-Coupled Receptors in Immunity, Coronary Artery Disease, and Cancer

    Edward J. Goetzl

    2002-01-01

    Full Text Available The physiological lysophospholipids (LPLs, exemplified by lysophosphatidic acid (LPA and sphingosine 1-phosphate (S1P, are omnific mediators of normal cellular proliferation, survival, and functions. Although both LPA and S1P attain micromolar concentrations in many biological fluids, numerous aspects of their biosynthesis, transport, and metabolic degradation are unknown. Eight members of a new subfamily of G protein-coupled LPA/S1P receptors, originally termed Edg Rs, bind either LPA or S1P with high affinity and transduce a series of growth-related and/or cytoskeleton-based functional responses. The most critical areas of LPL biology and pathobiology are neural development and neurodegeneration, immunity, atherosclerosis and myocardial injury, and cancer. Data from analyses of T cells established two basic points: (1 the plasticity and adaptability of expression of LPA/S1P Rs by some cells as a function of activation, and (2 the role of opposing signals from two different receptors for the same ligand as a mechanism for fine control of effects of LPLs. In the heart, LPLs may promote coronary atherosclerosis, but are effectively cytoprotective for hypoxic cardiac myocytes and those exposed to oxygen free radicals. The findings of production of LPA by some types of tumor cells, overexpression of selected sets of LPA receptors by the same tumor cells, and augmentation of the effects of protein growth factors by LPA have suggested pathogenetic roles for the LPLs in cancer. The breadth of physiologic and pathologic activities of LPLs emphasizes the importance of developing bioavailable nonlipid agonists and antagonists of the LPA/S1P receptors for diverse therapeutic applications.

  4. Angiotensin type 2 receptors

    Sumners, Colin; de Kloet, Annette D; Krause, Eric G

    2015-01-01

    In most situations, the angiotensin AT2-receptor (AT2R) mediates physiological actions opposing those mediated by the AT1-receptor (AT1R), including a vasorelaxant effect. Nevertheless, experimental evidence vastly supports that systemic application of AT2R-agonists is blood pressure neutral...

  5. Knock out of S1P3 receptor signaling attenuates inflammation and fibrosis in bleomycin-induced lung injury mice model.

    Ken Murakami

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive sphingolipid metabolite involved in many critical cellular processes, including proliferation, migration, and angiogenesis, through interaction with a family of five G protein-coupled receptors (S1P1-5. Some reports have implicated S1P as an important inflammatory mediator of the pathogenesis of airway inflammation, but the role of S1P3 in the pathogenesis of lung diseases is not completely understood. We used S1P3-deficient (knockout (KO mice to clarify the role of S1P3 receptor signaling in the pathogenesis of pulmonary inflammation and fibrosis using a bleomycin-induced model of lung injury. On the seventh day after bleomycin administration, S1P3 KO mice exhibited significantly less body weight loss and pulmonary inflammation than wild-type (WT mice. On the 28th day, there was less pulmonary fibrosis in S1P3 KO mice than in WT mice. S1P3 KO mice demonstrated a 56% reduction in total cell count in bronchoalveolar lavage fluid (BALF collected on the seventh day compared with WT mice; however, the differential white blood cell profiles were similar. BALF analysis on the seventh day showed that connective tissue growth factor (CTGF levels were significantly decreased in S1P3 KO mice compared with WT mice, although no differences were observed in monocyte chemotactic protein-1 (MCP-1 or transforming growth factor β1 (TGF-β1 levels. Finally, S1P levels in BALF collected on the 7th day after treatment were not significantly different between WT and S1P3 KO mice. Our results indicate that S1P3 receptor signaling plays an important role in pulmonary inflammation and fibrosis and that this signaling occurs via CTGF expression. This suggests that this pathway might be a therapeutic target for pulmonary fibrosis.

  6. The p110beta isoform of phosphoinositide 3-kinase signals downstream of G protein-coupled receptors and is functionally redundant with p110gamma.

    Guillermet-Guibert, Julie; Bjorklof, Katja; Salpekar, Ashreena; Gonella, Cristiano; Ramadani, Faruk; Bilancio, Antonio; Meek, Stephen; Smith, Andrew J H; Okkenhaug, Klaus; Vanhaesebroeck, Bart

    2008-06-17

    The p110 isoforms of phosphoinositide 3-kinase (PI3K) are acutely regulated by extracellular stimuli. The class IA PI3K catalytic subunits (p110alpha, p110beta, and p110delta) occur in complex with a Src homology 2 (SH2) domain-containing p85 regulatory subunit, which has been shown to link p110alpha and p110delta to Tyr kinase signaling pathways. The p84/p101 regulatory subunits of the p110gamma class IB PI3K lack SH2 domains and instead couple p110gamma to G protein-coupled receptors (GPCRs). Here, we show, using small-molecule inhibitors with selectivity for p110beta and cells derived from a p110beta-deficient mouse line, that p110beta is not a major effector of Tyr kinase signaling but couples to GPCRs. In macrophages, both p110beta and p110gamma contributed to Akt activation induced by the GPCR agonist complement 5a, but not by the Tyr kinase ligand colony-stimulating factor-1. In fibroblasts, which express p110beta but not p110gamma, p110beta mediated Akt activation by the GPCR ligands stromal cell-derived factor, sphingosine-1-phosphate, and lysophosphatidic acid but not by the Tyr kinase ligands PDGF, insulin, and insulin-like growth factor 1. Introduction of p110gamma in these cells reduced the contribution of p110beta to GPCR signaling. Taken together, these data show that p110beta and p110gamma can couple redundantly to the same GPCR agonists. p110beta, which shows a much broader tissue distribution than the leukocyte-restricted p110gamma, could thus provide a conduit for GPCR-linked PI3K signaling in the many cell types where p110gamma expression is low or absent.

  7. Blocking S1P interaction with S1P{sub 1} receptor by a novel competitive S1P{sub 1}-selective antagonist inhibits angiogenesis

    Fujii, Yasuyuki, E-mail: y.fujii@po.rd.taisho.co.jp [Department of Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co. Ltd., 1-403 Saitama, Saitama 331-9530 (Japan); Ueda, Yasuji; Ohtake, Hidenori; Ono, Naoya; Takayama, Tetsuo; Nakazawa, Kiyoshi [Department of Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co. Ltd., 1-403 Saitama, Saitama 331-9530 (Japan); Igarashi, Yasuyuki [Laboratory of Biomembrane and Biofunctional Chemistry, Hokkaido University, Sapporo, Hokkaido 060-0812 (Japan); Goitsuka, Ryo [Division of Development and Aging, Research Institute for Biological Sciences, Tokyo University of Science, Noda, Chiba 278-0022 (Japan)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer The effect of a newly developed S1P{sub 1}-selective antagonist on angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1} is a critical component of VEGF-related angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vitro activity to inhibit angiogenesis. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vivo activity to inhibit angiogenesis. Black-Right-Pointing-Pointer The efficacy of S1P{sub 1}-selective antagonist for anti-cancer therapies. -- Abstract: Sphingosine 1-phosphate receptor type 1 (S1P{sub 1}) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P{sub 1} and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P{sub 1}-selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P{sub 1} antagonists. TASP0277308 inhibited S1P- as well as VEGF-induced cellular responses, including migration and proliferation of human umbilical vein endothelial cells. Furthermore, TASP0277308 effectively blocked a VEGF-induced tube formation in vitro and significantly suppressed tumor cell-induced angiogenesis in vivo. These findings revealed that S1P{sub 1} is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

  8. The p110β isoform of phosphoinositide 3-kinase signals downstream of G protein-coupled receptors and is functionally redundant with p110γ

    Guillermet-Guibert, Julie; Bjorklof, Katja; Salpekar, Ashreena; Gonella, Cristiano; Ramadani, Faruk; Bilancio, Antonio; Meek, Stephen; Smith, Andrew J. H.; Okkenhaug, Klaus; Vanhaesebroeck, Bart

    2008-01-01

    The p110 isoforms of phosphoinositide 3-kinase (PI3K) are acutely regulated by extracellular stimuli. The class IA PI3K catalytic subunits (p110α, p110β, and p110δ) occur in complex with a Src homology 2 (SH2) domain-containing p85 regulatory subunit, which has been shown to link p110α and p110δ to Tyr kinase signaling pathways. The p84/p101 regulatory subunits of the p110γ class IB PI3K lack SH2 domains and instead couple p110γ to G protein-coupled receptors (GPCRs). Here, we show, using small-molecule inhibitors with selectivity for p110β and cells derived from a p110β-deficient mouse line, that p110β is not a major effector of Tyr kinase signaling but couples to GPCRs. In macrophages, both p110β and p110γ contributed to Akt activation induced by the GPCR agonist complement 5a, but not by the Tyr kinase ligand colony-stimulating factor-1. In fibroblasts, which express p110β but not p110γ, p110β mediated Akt activation by the GPCR ligands stromal cell-derived factor, sphingosine-1-phosphate, and lysophosphatidic acid but not by the Tyr kinase ligands PDGF, insulin, and insulin-like growth factor 1. Introduction of p110γ in these cells reduced the contribution of p110β to GPCR signaling. Taken together, these data show that p110β and p110γ can couple redundantly to the same GPCR agonists. p110β, which shows a much broader tissue distribution than the leukocyte-restricted p110γ, could thus provide a conduit for GPCR-linked PI3K signaling in the many cell types where p110γ expression is low or absent. PMID:18544649

  9. Individual variation of human S1P₁ coding sequence leads to heterogeneity in receptor function and drug interactions.

    Obinata, Hideru; Gutkind, Sarah; Stitham, Jeremiah; Okuno, Toshiaki; Yokomizo, Takehiko; Hwa, John; Hla, Timothy

    2014-12-01

    Sphingosine 1-phosphate receptor 1 (S1P₁), an abundantly-expressed G protein-coupled receptor which regulates key vascular and immune responses, is a therapeutic target in autoimmune diseases. Fingolimod/Gilenya (FTY720), an oral medication for relapsing-remitting multiple sclerosis, targets S1P₁ receptors on immune and neural cells to suppress neuroinflammation. However, suppression of endothelial S1P₁ receptors is associated with cardiac and vascular adverse effects. Here we report the genetic variations of the S1P₁ coding region from exon sequencing of >12,000 individuals and their functional consequences. We conducted functional analyses of 14 nonsynonymous single nucleotide polymorphisms (SNPs) of the S1PR1 gene. One SNP mutant (Arg¹²⁰ to Pro) failed to transmit sphingosine 1-phosphate (S1P)-induced intracellular signals such as calcium increase and activation of p44/42 MAPK and Akt. Two other mutants (Ile⁴⁵ to Thr and Gly³⁰⁵ to Cys) showed normal intracellular signals but impaired S1P-induced endocytosis, which made the receptor resistant to FTY720-induced degradation. Another SNP mutant (Arg¹³ to Gly) demonstrated protection from coronary artery disease in a high cardiovascular risk population. Individuals with this mutation showed a significantly lower percentage of multi-vessel coronary obstruction in a risk factor-matched case-control study. This study suggests that individual genetic variations of S1P₁ can influence receptor function and, therefore, infer differential disease risks and interaction with S1P₁-targeted therapeutics. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

  10. Angiotensin type 2 receptor (AT2R) and receptor Mas

    Villela, Daniel; Leonhardt, Julia; Patel, Neal

    2015-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striki...

  11. Role of sphingolipids in murine radiation-induced lung injury: protection by sphingosine 1-phosphate analogs

    Mathew, Biji; Jacobson, Jeffrey R.; Berdyshev, Evgeny; Huang, Yong; Sun, Xiaoguang; Zhao, Yutong; Gerhold, Lynnette M.; Siegler, Jessica; Evenoski, Carrie; Wang, Ting; Zhou, Tong; Zaidi, Rafe; Moreno-Vinasco, Liliana; Bittman, Robert; Chen, Chin Tu

    2011-01-01

    Clinically significant radiation-induced lung injury (RILI) is a common toxicity in patients administered thoracic radiotherapy. Although the molecular etiology is poorly understood, we previously characterized a murine model of RILI in which alterations in lung barrier integrity surfaced as a potentially important pathobiological event and genome-wide lung gene mRNA levels identified dysregulation of sphingolipid metabolic pathway genes. We hypothesized that sphingolipid signaling components...

  12. Sphingosine-1-phosphate in the lymphatic fluid determined by novel methods

    Masayuki Nagahashi

    2016-12-01

    Conclusions: In agreement with the previous theory, our results confirm “S1P gradient” among blood, lymphatic fluid and peripheral lymphatic tissues. Convenient methods for collection and measurement of sphingolipids in lymphatic fluid are expected to provide new insights on functions of sphingolipids.

  13. Sphingosine-1-Phosphate reduces ischemia/reperfusion injury by phosphorylating the gap junction protein Connexin43

    Morel, Sandrine; Christoffersen, Christina; Axelsen, Lene N

    2016-01-01

    recruitment seems only indirectly affected. Importantly, short-term S1P treatment at the onset of reperfusion was sufficient to reduce ischemia/reperfusion injury in isolated perfused hearts. Mechanistic in vitro and ex vivo studies revealed that 5 min of S1P treatment induced phosphorylation of the gap...

  14. Sphingosine-1-phosphate signalling induces the production of Lcn-2 by macrophages to promote kidney regeneration

    Sola, Anna; Weigert, Andreas; Jung, Michaela

    2011-01-01

    Inflammatory reactions are initiated to eliminate pathogens, but also to promote repair of damaged tissue after acute inflammation is terminated. In this regard, macrophages play a prominent role during induction as well as resolution of inflammation and injury in various organs including...

  15. Low expression of IL-18 and IL-18 receptor in human skeletal muscle is associated with systemic and intramuscular lipid metabolism-Role of HIV lipodystrophy

    Lindegaard, Birgitte; Hvid, Thine; Wolsk Mygind, Helene

    2018-01-01

    receptor (R) expression would be altered in patients with HIV-lipodystrophy. DESIGN AND METHODS: Twenty-three HIV-infected patients with LD and 15 age-matched healthy controls were included in a cross-sectional study. Biopsies from the vastus lateralis muscle were obtained and IL-18 and IL-18R m......-18 mRNA is expressed in human skeletal muscle but a role for IL-18 in muscle has not been identified. Patients with HIV-infection and lipodystrophy (LD) are characterized by lipid and glucose disturbances and increased levels of circulating IL-18. We hypothesized that skeletal muscle IL-18 and IL-18......RNA expression were measured by real-time PCR and sphingolipids (ceramides, sphingosine, sphingosine-1-Phosphate, sphinganine) were measured by HPLC. Insulin resistance was assessed by HOMA and the insulin response during an OGTT. RESULTS: Patients with HIV-LD had a 60% and 54% lower level of muscular IL-18...

  16. C-Type Lectin Receptors in Asthma

    Sabelo Hadebe

    2018-04-01

    Full Text Available Asthma is a heterogeneous disease that affects approximately 300 million people worldwide, largely in developed countries. The etiology of the disease is poorly understood, but is likely to involve specific innate and adaptive responses to inhaled microbial components that are found in allergens. Fungal-derived allergens represent a major contributing factor in the initiation, persistence, exacerbation, and severity of allergic asthma. C-type lectin like receptors, such as dectin-1, dectin-2, DC-specific intercellular adhesion molecule 3-grabbing nonintegrin, and mannose receptor, recognize many fungal-derived allergens and other structurally similar allergens derived from house dust mites (HDM. In some cases, the fungal derived allergens have been structurally and functionally identified alongside their respective receptors in both humans and mice. In this review, we discuss recent understanding on how selected fungal and HDM derived allergens as well as their known or unknown receptors shape allergic airway diseases.

  17. Fingolimod modulates microglial activation to augment markers of remyelination

    Baker David

    2011-07-01

    Full Text Available Abstract Introduction Microglial activation in multiple sclerosis has been postulated to contribute to long-term neurodegeneration during disease. Fingolimod has been shown to impact on the relapsing remitting phase of disease by modulating autoreactive T-cell egress from lymph organs. In addition, it is brain penetrant and has been shown to exert multiple effects on nervous system cells. Methods In this study, the impact of fingolimod and other sphingosine-1-phosphate receptor active molecules following lysophosphotidyl choline-induced demyelination was examined in the rat telencephalon reaggregate, spheroid cell culture system. The lack of immune system components allowed elucidation of the direct effects of fingolimod on CNS cell types in an organotypic situation. Results Following demyelination, fingolimod significantly augmented expression of myelin basic protein in the remyelination phase. This increase was not associated with changes in neurofilament levels, indicating de novo myelin protein expression not associated with axonal branching. Myelin wrapping was confirmed morphologically using confocal and electron microscopy. Increased remyelination was associated with down-regulation of microglial ferritin, tumor necrosis factor alpha and interleukin 1 during demyelination when fingolimod was present. In addition, nitric oxide metabolites and apoptotic effectors caspase 3 and caspase 7 were reduced during demyelination in the presence of fingolimod. The sphingosine-1-phosphate receptor 1 and 5 agonist BAF312 also increased myelin basic protein levels, whereas the sphingosine-1-phosphate receptor 1 agonist AUY954 failed to replicate this effect on remyelination. Conclusions The results presented indicate that modulation of S1P receptors can ameliorate pathological effectors associated with microglial activation leading to a subsequent increase in protein and morphological markers of remyelination. In addition, sphingosine-1-phosphate

  18. The Expression Profiles of Lysophospholipid Receptors (LPLRs in Different Endothelial Cells

    Yu-Wei Lee

    2006-03-01

    Full Text Available Sphingosine-1-phosphate (S1P and lysophosphatidic acid (LPA are two bioactive lysophospholipids (LPLs, stored primarily in platelets and released during platelet activation. Both LPLs are capable of regulating endothelial cell functions. The physiological functions of S1P and LPA are mediated by interacting with eight different G-protein coupled receptors: S1P1 through 5 and LPA1 through 3, which activate three different heterotrimeric GTP proteins-including Gi、Gq and G(12/13. The expression of LPL receptors in endothelial cells would affect the responses of S1P and LPA to these cells. There is no previous report discussing the expression profiles of LPL receptors in different endothelial cells from various species. In this study, we aim to investigate the expression profiles of S1P and LPA receptors in different endothelial cells isolated from human, rat, mouse and bovine origin. We used RT-PCR to determine LPLs receptors expression profiles in different endothelial cells. Our results indicated that endothelial cells from various species express different LPL receptors. Endothelial cells isolated from the same source of different species also had different LPLs receptors expression profiles. Therefore, different endothelial cells should respond to LPLs in different manners.

  19. Estrogen-Modulated Response of Breast Cancer To Vitamin D and Its Analogs: Role of IGF

    Dolezalova, Hana

    1999-01-01

    ... (LPA) and sphingosine 1-phosphate (S1P). Estrogen receptor positive and estrogen receptor negative cells express predominantly Edg-2 and Edg-4 Rs for LPA and Edg-3 for Sip, which transduce proliferative responses by direct nuclear signaling...

  20. Validation of a rapid, non-radioactive method to quantify internalisation of G-protein coupled receptors.

    Jongsma, Maikel; Florczyk, Urszula M; Hendriks-Balk, Mariëlle C; Michel, Martin C; Peters, Stephan L M; Alewijnse, Astrid E

    2007-07-01

    Agonist exposure can cause internalisation of G-protein coupled receptors (GPCRs), which may be a part of desensitisation but also of cellular signaling. Previous methods to study internalisation have been tedious or only poorly quantitative. Therefore, we have developed and validated a quantitative method using a sphingosine-1-phosphate (S1P) receptor as a model. Because of a lack of suitable binding studies, it has been difficult to study S1P receptor internalisation. Using a N-terminal HisG-tag, S1P(1) receptors on the cell membrane can be visualised via immunocytochemistry with a specific anti-HisG antibody. S1P-induced internalisation was concentration dependent and was quantified using a microplate reader, detecting either absorbance, a fluorescent or luminescent signal, depending on the antibodies used. Among those, the fluorescence detection method was the most convenient to use. The relative ease of this method makes it suitable to measure a large number of data points, e.g. to compare the potency and efficacy of receptor ligands.

  1. Effects of sphingosine-1-phosphate on gene expression of two cell mouse embryos induced by C2-Ceramide

    Xujing Geng

    2014-06-01

    Conclusions: This study provides a map of genes in the pre-implantation two cell mouse embryo. Further investigation based on these data will provide a better understanding of the effects of S1P on the pre-implantation embryos in other mammalian species, especially human.

  2. High expression of sphingosine kinase 1 and S1P receptors in chemotherapy-resistant prostate cancer PC3 cells and their camptothecin-induced up-regulation

    Akao, Yukihiro; Banno, Yoshiko; Nakagawa, Yoshihito; Hasegawa, Nobuko; Kim, Tack-Joong; Murate, Takashi; Igarashi, Yasuyuki; Nozawa, Yoshinori

    2006-01-01

    Although most of pharmacological therapies for cancer utilize the apoptotic machinery of the cells, the available anti-cancer drugs are limited due to the ability of prostate cancer cells to escape from the anti-cancer drug-induced apoptosis. A human prostate cancer cell line PC3 is resistant to camptothecin (CPT). To elucidate the mechanism of this resistance, we have examined the involvement of sphingosine kinase (SPHK) and sphingosine 1-phosphate (S1P) receptor in CPT-resistant PC3 and -sensitive LNCaP cells. PC3 cells exhibited higher activity accompanied with higher expression levels of protein and mRNA of SPHK1, and also elevated expression of S1P receptors, S1P 1 and S1P 3 , as compared with those of LNCaP cells. The knockdown of SPHK1 by small interfering RNA and inhibition of S1P receptor signaling by pertussis toxin in PC3 cells induced significant inhibition of cell growth, suggesting implication of SPHK1 and S1P receptors in cell proliferation in PC3 cells. Furthermore, the treatment of PC3 cells with CPT was found to induce up-regulation of the SPHK1/S1P signaling by induction of both SPHK1 enzyme and S1P 1 /S1P 3 receptors. These findings strongly suggest that high expression and up-regulation of SPHK1 and S1P receptors protect PC3 cells from the apoptosis induced by CPT

  3. Genetic evidence for involvement of neuronally expressed S1P₁ receptor in nociceptor sensitization and inflammatory pain.

    Norbert Mair

    2011-02-01

    Full Text Available Sphingosine-1-phosphate (S1P is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P₁ receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P₁ receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P₁ receptor. Our data show that neuronally expressed S1P₁ receptors play a significant role in regulating nociceptor function and that S1P/S1P₁ signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation.

  4. Chimeric opioid peptides: tools for identifying opioid receptor types.

    Xie, G X; Miyajima, A; Yokota, T; Arai, K; Goldstein, A

    1990-01-01

    We synthesized several chimeric peptides in which the N-terminal nine residues of dynorphin-32, a peptide selective for the kappa opioid receptor, were replaced by opioid peptides selective for other opioid receptor types. Each chimeric peptide retained the high affinity and type selectivity characteristic of its N-terminal sequence. The common C-terminal two-thirds of the chimeric peptides served as an epitope recognized by the same monoclonal antibody. When bound to receptors on a cell surf...

  5. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS

    Leonhardt, Julia; Villela, Daniel C.; Teichmann, Anke

    2017-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may in...

  6. The effect of S1P receptor signaling pathway on the survival and drug resistance in multiple myeloma cells.

    Fu, Di; Li, Yingchun; Li, Jia; Shi, Xiaoyan; Yang, Ronghui; Zhong, Yuan; Wang, Huihan; Liao, Aijun

    2017-01-01

    Multiple myeloma (MM) remains incurable by conventional chemotherapy. Sphingosine-1-phosphate (S1P) receptor-mediated signaling has been recently demonstrated to have critical roles in cell survival and drug resistance in a number of hematological malignancies. To dissect the roles of S1P receptor pathway in MM, we systematically examined cell viability and protein expression associated with cell survival and drug resistance in MM cell lines upon treatment with either pathway activator (S1P) or inhibitor (FTY720). Our results reveal that FTY720 inhibits cell proliferation by downregulating expression of target genes, while S1P has an opposite effect. Knocking down of S1P receptor S1P5R results in a reduction of cell survival-related gene expression; however, it does not have impacts on expression of drug resistance genes. These results suggest that S1P signaling plays a role in cell proliferation and drug resistance in MM, and targeting this pathway will provide a new therapeutic direction for MM management.

  7. Modeling Tolerance Development for the Effect on Heart Rate of the Selective S1P1 Receptor Modulator Ponesimod.

    Lott, Dominik; Lehr, Thorsten; Dingemanse, Jasper; Krause, Andreas

    2017-09-15

    Ponesimod is a selective sphingosine-1-phosphate-1 (S1P 1 ) receptor modulator currently under investigation for the treatment of multiple sclerosis. S1P receptor modulators reduce heart rate following treatment initiation. This effect disappears with repeated dosing, enabling development of innovative uptitration regimens to optimize patient safety. There are currently no published pharmacokinetic/pharmacodynamic models describing the heart rate reduction of S1P receptor modulators in humans. The model developed here provides quantification of this effect for ponesimod. A direct-effect I max model with estimated maximum reduction of 45%, tolerance development, and circadian variation best described this effect. The pooled data from nine clinical studies enabled characterization of interindividual variability. The model was used to simulate different treatment regimens to compare the effect of high initial doses vs. gradual uptitration with respect to the occurrence of bradycardia. The results indicate a better safety profile when using gradual uptitration. The model allows studying dosing regimens not clinically tested in silico. © 2017 American Society for Clinical Pharmacology and Therapeutics.

  8. Computer modeling of Cannabinoid receptor type 1

    Sapundzhi Fatima

    2018-01-01

    Full Text Available Cannabinoid receptors are important class of receptors as they are involved in various physiological processes such as appetite, pain-sensation, mood, and memory. It is important to design receptor-selective ligands in order to treat a particular disorder. The aim of the present study is to model the structure of cannabinoid receptor CB1 and to perform docking between obtained models and known ligands. Two models of CBR1 were prepared with two different methods (Modeller of Chimera and MOE. They were used for docking with GOLD 5.2. It was established a high correlation between inhibitory constant Ki of CB1 cannabinoid ligands and the ChemScore scoring function of GOLD, which concerns both models. This suggests that the models of the CB1 receptors obtained could be used for docking studies and in further investigation and design of new potential, selective and active cannabinoids with the desired effects.

  9. Chimeric opioid peptides: Tools for identifying opioid receptor types

    Xie, G.; Miyajima, A.; Yokota, T.; Arai, K.; Goldstein, A.

    1990-01-01

    The authors synthesized several chimeric [125J-labelled] peptides in which the N-terminal nine residues of dynorphin-32, a peptide selective for the κ opioid receptor, were replaced by opioid peptides selective for other opioid receptor types. Each chimeric peptide retained the high affinity and type selectivity characteristic of its N-terminal sequence. The common C-terminal two-thirds of the chimeric peptides served as an epitope recognized by the same monoclonal antibody. When bound to receptors on a cell surface or membrane preparation, these peptides could still bind specifically to the monoclonal antibody. These chimeric peptides should be useful for isolating μ, δ, and κ opioid receptors and for identifying opioid receptors on transfected cells in expression cloning procedures. The general approach using chimeric peptides should be applicable to other peptide receptors

  10. Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology

    Callihan Phillip

    2008-12-01

    Full Text Available Abstract Background Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development. Results Our results demonstrate that Lysophosphatidic Acid (LPA and Sphingosine-1-phosphate (S1P receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to Gi/o G-proteins that inhibit adenylyl cyclase and to Gq-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via Gi/o coupled receptors in an Epidermal Growth Factor Receptor (EGFR- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK. Conclusion Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors.

  11. Modeling the Effect of the Selective S1P1 Receptor Modulator Ponesimod on Subsets of Blood Lymphocytes.

    Lott, Dominik; Krause, Andreas; Seemayer, Christian A; Strasser, Daniel S; Dingemanse, Jasper; Lehr, Thorsten

    2017-03-01

    This analysis aimed at describing the effect of the selective sphingosine-1-phosphate receptor 1 modulator ponesimod on lymphocyte subsets in peripheral blood. As the involvement of different lymphocyte subsets varies among different autoimmune diseases, characterizing the effect of ponesimod on these may be beneficial in better understanding treatment effects. Three phase 1 clinical studies in healthy human subjects were pooled. Non-linear mixed-effects modeling techniques were used to study the effect of ponesimod on lymphocyte subsets such as B cells, T helper cells, T cytotoxic cells, and natural killer cells in a qualitative and quantitative manner. Indirect-response I max models including circadian variation best described the effect of ponesimod on lymphocyte subsets. B cells and T helper cells were shown to be more affected compared to T cytotoxic cells with respect to the maximum possible reduction (100% for B and T helper cells, 95% for T cytotoxic cells) and the concentration required to reach half the maximum effect. Inter-individual variability was found to be larger for T cytotoxic compared to T helper, and B cells. These first models for ponesimod on the level of lymphocyte subsets offer a valuable tool for the analysis and interpretation of results from ponesimod trials in autoimmune diseases.

  12. Metabotropic glutamate receptor type 1 autoimmunity

    Lopez-Chiriboga, A. Sebastian; Komorowski, Lars; Kümpfel, Tania; Probst, Christian; Hinson, Shannon R.; Pittock, Sean J.

    2016-01-01

    Objective: To describe retrospectively the clinical associations of immunoglobulin G (IgG) targeting metabotropic glutamate receptor 1 (mGluR1-IgG). Methods: Specimens of 9 patients evaluated on a service basis in the Mayo Clinic Neuroimmunology Laboratory by tissue-based immunofluorescence assay (IFA) yielded a robust, synaptic immunostaining pattern consistent with mGluR1-IgG (serum, 9; CSF, 2 available). Transfected HEK293 cell-based assay (CBA) confirmed mGluR1 specificity in all 11 specimens. A further 2 patients were detected in Germany primarily by CBA. Results: The median symptom onset age for the 11 patients was 58 years (range 33–81 years); 6 were male. All 9 Mayo Clinic patients had subacute onset of cerebellar ataxia, 4 had dysgeusia, 1 had psychiatric symptoms, and 1 had cognitive impairment. All were evaluated for malignancy, but only 1 was affected (cutaneous T-cell lymphoma). One developed ataxia post–herpes zoster infection. Head MRIs were generally atrophic or normal-appearing, and CSF was inflammatory in just 1 of 5 tested, though mGluR1-IgG was detected in both specimens submitted. Five patients improved (attributable to immunotherapy in 4, spontaneously in 1), 3 stabilized (attributable to immunotherapy in 2, cancer therapy in 1), and 1 progressively declined (untreated). The 2 German patients had ataxia, but fulfilled multiple sclerosis diagnostic criteria (1 relapsing-remitting, 1 progressive). However, both had histories of hematologic malignancy (acute lymphocytic leukemia and mantle cell lymphoma), and had mGluR1-IgG detected in serum by CBA (weakly positive on tissue-based IFA). Conclusions: mGluR1 autoimmunity represents a treatable form of cerebellar ataxia. Dysgeusia may be a diagnostic clue. Paraneoplastic, parainfectious, or idiopathic causes may occur. PMID:26888994

  13. Glucocorticoid receptors in monocytes in type 1 diabetes mellitus

    Damm, P; Binder, C

    1989-01-01

    Glucocorticoid receptor binding characteristics were investigated in 8 males with poorly controlled Type 1 diabetes mellitus and 14 healthy males. The cell type studied was monocytes, and a method for correction for heterogeneity in glucocorticoid binding in a mononuclear leucocyte population...... or with HbA1c. In conclusion, no major abnormalities in glucocorticoid receptor binding characteristics could be demonstrated in Type 1 diabetes mellitus....... was introduced. The number of receptors and the dissociation constant KD were, respectively, 13,699 and 2.93 X 10(-8) mol/l for the control group and 15,788 and 2.75 X 10(-8) mol/l for diabetics (p greater than 0.05). In diabetics, KD correlated negatively with blood glucose (r = 0.762, p less than 0...

  14. Delivery of S1P receptor-targeted drugs via biodegradable polymer scaffolds enhances bone regeneration in a critical size cranial defect.

    Das, Anusuya; Tanner, Shaun; Barker, Daniel A; Green, David; Botchwey, Edward A

    2014-04-01

    Biodegradable polymer scaffolds can be used to deliver soluble factors to enhance osseous remodeling in bone defects. To this end, we designed a poly(lactic-co-glycolic acid) (PLAGA) microsphere scaffold to sustain the release of FTY720, a selective agonist for sphingosine 1-phosphate (S1P) receptors. The microsphere scaffolds were created from fast degrading 50:50 PLAGA and/or from slow-degrading 85:15 PLAGA. Temporal and spatial regulation of bone remodeling depended on the use of appropriate scaffolds for drug delivery. The release profiles from the scaffolds were used to design an optimal delivery system to treat critical size cranial defects in a rodent model. The ability of local FTY720 delivery to maximize bone regeneration was evaluated with micro-computed tomography (microCT) and histology. Following 4 weeks of defect healing, FTY720 delivery from 85:15 PLAGA scaffolds resulted in a significant increase in bone volumes in the defect region compared to the controls. A 85:15 microsphere scaffolds maintain their structural integrity over a longer period of time, and cause an initial burst release of FTY720 due to surface localization of the drug. This encourages cellular in-growth and an increase in new bone formation. Copyright © 2013 Wiley Periodicals, Inc.

  15. Delivery of S1P Receptor-Targeted Drugs via Biodegradable Polymer Scaffolds Enhances Bone Regeneration in a Critical Size Cranial Defect*

    Das, Anusuya; Tanner, Shaun; Barker, Daniel A.; Green, David; Botchwey, Edward A.

    2014-01-01

    Biodegradable polymer scaffolds can be used to deliver soluble factors to enhance osseous remodeling in bone defects. To this end, we designed a poly(lactic-co-glycolic acid) (PLAGA) microsphere scaffold to sustain the release of FTY720, a selective agonist for sphingosine 1-phosphate (S1P) receptors. The microsphere scaffolds were created from fast degrading 50:50 PLAGA and/or from slow-degrading 85:15 PLAGA. Temporal and spatial regulation of bone remodeling depended on the use of appropriate scaffolds for drug delivery. The release profiles from the scaffolds were used to design an optimal delivery system to treat critical size cranial defects in a rodent model. The ability of local FTY720 delivery to maximize bone regeneration was evaluated with microcomputed tomography (microCT) and histology. Following 4 weeks of defect healing, FTY720 delivery from 85:15 PLAGA scaffolds resulted in a significant increase in bone volumes in the defect region compared to the controls. 85:15 microsphere scaffolds maintain their structural integrity over a longer period of time, and cause an initial burst release of FTY720 due to surface localization of the drug. This encourages cellular in-growth and an increase in new bone formation. PMID:23640833

  16. Involvement of Gβγ subunits of Gi protein coupled with S1P receptor on multivesicular endosomes in F-actin formation and cargo sorting into exosomes.

    Kajimoto, Taketoshi; Mohamed, Nesma Nabil Ibrahim; Badawy, Shaymaa Mohamed Mohamed; Matovelo, Shubi Ambwene; Hirase, Mitsuhiro; Nakamura, Shunsuke; Yoshida, Daisuke; Okada, Taro; Ijuin, Takeshi; Nakamura, Shun-Ichi

    2018-01-05

    Exosomes play a critical role in cell-to-cell communication by delivering cargo molecules to recipient cells. However, the mechanism underlying the generation of the exosomal multivesicular endosome (MVE) is one of the mysteries in the field of endosome research. Although sphingolipid metabolites such as ceramide and sphingosine 1-phosphate (S1P) are known to play important roles in MVE formation and maturation, the detailed molecular mechanisms are still unclear. Here, we show that Rho family GTPases, including Cdc42 and Rac1, are constitutively activated on exosomal MVEs and are regulated by S1P signaling as measured by fluorescence resonance energy transfer (FRET)-based conformational changes. Moreover, we detected S1P signaling-induced filamentous actin (F-actin) formation. A selective inhibitor of Gβγ subunits, M119, strongly inhibited both F-actin formation on MVEs and cargo sorting into exosomal intralumenal vesicles of MVEs, both of which were fully rescued by the simultaneous expression of constitutively active Cdc42 and Rac1. Our results shed light on the mechanism underlying exosomal MVE maturation and inform the understanding of the physiological relevance of continuous activation of the S1P receptor and subsequent downstream G protein signaling to Gβγ subunits/Rho family GTPases-regulated F-actin formation on MVEs for cargo sorting into exosomal intralumenal vesicles. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Oncogenic S1P signalling in EBV-associated nasopharyngeal carcinoma activates AKT and promotes cell migration through S1P receptor 3.

    Lee, Hui Min; Lo, Kwok-Wai; Wei, Wenbin; Tsao, Sai Wah; Chung, Grace Tin Yun; Ibrahim, Maha Hafez; Dawson, Christopher W; Murray, Paul G; Paterson, Ian C; Yap, Lee Fah

    2017-05-01

    Undifferentiated nasopharyngeal carcinoma (NPC) is a cancer with high metastatic potential that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we have investigated the functional contribution of sphingosine-1-phosphate (S1P) signalling to the pathogenesis of NPC. We show that EBV infection or ectopic expression of the EBV-encoded latent genes (EBNA1, LMP1, and LMP2A) can up-regulate sphingosine kinase 1 (SPHK1), the key enzyme that produces S1P, in NPC cell lines. Exogenous addition of S1P promotes the migration of NPC cells through the activation of AKT; shRNA knockdown of SPHK1 resulted in a reduction in the levels of activated AKT and inhibition of cell migration. We also show that S1P receptor 3 (S1PR3) mRNA is overexpressed in EBV-positive NPC patient-derived xenografts and a subset of primary NPC tissues, and that knockdown of S1PR3 suppressed the activation of AKT and the S1P-induced migration of NPC cells. Taken together, our data point to a central role for EBV in mediating the oncogenic effects of S1P in NPC and identify S1P signalling as a potential therapeutic target in this disease. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  18. Impact of Demographics, Organ Impairment, Disease, Formulation, and Food on the Pharmacokinetics of the Selective S1P1 Receptor Modulator Ponesimod Based on 13 Clinical Studies.

    Lott, Dominik; Lehr, Thorsten; Dingemanse, Jasper; Krause, Andreas

    2017-04-01

    Ponesimod is a selective, orally active sphingosine-1-phosphate receptor 1 modulator currently undergoing clinical evaluation for the treatment of multiple sclerosis (MS) in phase III clinical trials. Ponesimod dose-dependently reduces peripheral blood lymphocyte counts by blocking the egress of lymphocytes from lymphoid organs. A population pharmacokinetic (PK) analysis was performed based on pooled data from 13 clinical studies. Interindividual variability (IIV) and the impact of key demographic variables and other covariates on ponesimod exposure were assessed quantitatively. A two-compartment model with sequential zero/first-order absorption, including lag time, intercompartmental drug flow, and first-order clearance, adequately described the PK of ponesimod. Body weight, race, MS, psoriasis, hepatic impairment, drug formulation, and food were identified to significantly affect the concentration-time profile. The inclusion of these covariates into the model explained approximately 25 % of the IIV in the PK of ponesimod. Model predictions indicated that the impact of the identified covariates on ponesimod steady-state exposure is within 20 % of exposure, and thus within the margins of the IIV, with the exception of hepatic impairment. Changes up to threefold were predicted for severe cases of liver dysfunction. The rich data set enabled building a comprehensive population PK model that accurately predicts the concentration-time data of ponesimod. Covariates other than hepatic impairment were considered not clinically relevant and thus do not require dose adjustment. A potential dose adaptation can be conducted based on the final model.

  19. Signalling through C-type lectin receptors: shaping immune responses

    Geijtenbeek, Teunis B. H.; Gringhuis, Sonja I.

    2009-01-01

    C-type lectin receptors (CLRs) expressed by dendritic cells are crucial for tailoring immune responses to pathogens. Following pathogen binding, CLRs trigger distinct signalling pathways that induce the expression of specific cytokines which determine T cell polarization fates. Some CLRs can induce

  20. Differential S1P Receptor Profiles on M1- and M2-Polarized Macrophages Affect Macrophage Cytokine Production and Migration.

    Müller, Jan; von Bernstorff, Wolfram; Heidecke, Claus-Dieter; Schulze, Tobias

    2017-01-01

    Introduction . Macrophages are key players in complex biological processes. In response to environmental signals, macrophages undergo polarization towards a proinflammatory (M1) or anti-inflammatory (M2) phenotype. Sphingosine 1-phosphate (S1P) is a bioactive lysophospholipid that acts via 5 G-protein coupled receptors (S1P 1-5 ) in order to influence a broad spectrum of biological processes. This study assesses S1P receptor expression on macrophages before and after M1 and M2 polarization and performs a comparative analysis of S1P signalling in the two activational states of macrophages. Methods . Bone marrow derived macrophages (BMDM) from C57 BL/6 mice were cultured under either M1- or M2-polarizing conditions. S1P-receptor expression was determined by quantitative RT-PCR. Influence of S1P on macrophage activation, migration, phagocytosis, and cytokine secretion was assessed in vitro. Results . All 5 S1P receptor subclasses were expressed in macrophages. Culture under both M1- and M2-polarizing conditions led to significant downregulation of S1P 1 . In contrast, M1-polarized macrophages significantly downregulated S1P 4 . The expression of the remaining three S1P receptors did not change. S1P increased expression of iNOS under M2-polarizing conditions. Furthermore, S1P induced chemotaxis in M1 macrophages and changed cytokine production in M2 macrophages. Phagocytosis was not affected by S1P-signalling. Discussion . The expression of different specific S1P receptor profiles may provide a possibility to selectively influence M1- or M2-polarized macrophages.

  1. Berberine reduces fibronectin expression by suppressing the S1P-S1P2 receptor pathway in experimental diabetic nephropathy models.

    Kaipeng Huang

    Full Text Available The accumulation of glomerular extracellular matrix (ECM is one of the critical pathological characteristics of diabetic renal fibrosis. Fibronectin (FN is an important constituent of ECM. Our previous studies indicate that the activation of the sphingosine kinase 1 (SphK1-sphingosine 1- phosphate (S1P signaling pathway plays a key regulatory role in FN production in glomerular mesangial cells (GMCs under diabetic condition. Among the five S1P receptors, the activation of S1P2 receptor is the most abundant. Berberine (BBR treatment also effectively inhibits SphK1 activity and S1P production in the kidneys of diabetic models, thus improving renal injury. Based on these data, we further explored whether BBR could prevent FN production in GMCs under diabetic condition via the S1P2 receptor. Here, we showed that BBR significantly down-regulated the expression of S1P2 receptor in diabetic rat kidneys and GMCs exposed to high glucose (HG and simultaneously inhibited S1P2 receptor-mediated FN overproduction. Further, BBR also obviously suppressed the activation of NF-κB induced by HG, which was accompanied by reduced S1P2 receptor and FN expression. Taken together, our findings suggest that BBR reduces FN expression by acting on the S1P2 receptor in the mesangium under diabetic condition. The role of BBR in S1P2 receptor expression regulation could closely associate with its inhibitory effect on NF-κB activation.

  2. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS.

    Leonhardt, Julia; Villela, Daniel C; Teichmann, Anke; Münter, Lisa-Marie; Mayer, Magnus C; Mardahl, Maibritt; Kirsch, Sebastian; Namsolleck, Pawel; Lucht, Kristin; Benz, Verena; Alenina, Natalia; Daniell, Nicholas; Horiuchi, Masatsugu; Iwai, Masaru; Multhaup, Gerhard; Schülein, Ralf; Bader, Michael; Santos, Robson A; Unger, Thomas; Steckelings, Ulrike Muscha

    2017-06-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency of 10.8 ± 0.8%, indicating that AT2R and MAS are capable to form heterodimers. Heterodimerization was verified by competition experiments using untagged AT2R and MAS. Specificity of dimerization of AT2R and MAS was supported by lack of dimerization with the transient receptor potential cation channel, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked by an AT2R antagonist (PD123319) and also by a MAS antagonist (A-779). Knockout of a single of these receptors made astrocytes unresponsive for both agonists. Our results suggest that MAS and the AT2R form heterodimers and that-at least in astrocytes-both receptors functionally depend on each other. © 2017 American Heart Association, Inc.

  3. The angiotensin II type 1 receptor antagonist Losartan binds and activates bradykinin B2 receptor signaling

    Bonde, Marie Mi; Olsen, Kristine Boisen; Erikstrup, Niels

    2011-01-01

    The angiotensin II type 1 receptor (AT1R) blocker (ARB) Losartan has cardioprotective effects during ischemia-reperfusion injury and inhibits reperfusion arrhythmias -effects that go beyond the benefits of lowering blood pressure. The renin-angiotensin and kallikrein-kinin systems are intricately...

  4. Macrophage galactose-type C-type lectin receptor for DC targeting of antitumor glycopeptide vaccines

    Nuti, M; Zizzari, I; Napoletano, C

    2011-01-01

    e13528 Background: Dendritic cells (DCs) are the most potent antigen presenting cells and are employed in cancer vaccination. Several receptors are being studied in order to identif strategies to increase DCs activating capacity. The C-type lectin macrophage galactose type C-type lectin (MGL...... of IFNg and IL-2 secretion by both CD8 and CD4 T cells. CONCLUSIONS: These results demonstrate that MGL engagement profoundly affects DC plasticity inducing and directing a Th1 immune response. Moreover, MGL receptor expressed on human DC can be targeted by glycopeptide based vaccines with adjuvant...

  5. Identification of type II and type III pyoverdine receptors from Pseudomonas aeruginosa.

    de Chial, Magaly; Ghysels, Bart; Beatson, Scott A; Geoffroy, Valérie; Meyer, Jean Marie; Pattery, Theresa; Baysse, Christine; Chablain, Patrice; Parsons, Yasmin N; Winstanley, Craig; Cordwell, Stuart J; Cornelis, Pierre

    2003-04-01

    Pseudomonas aeruginosa produces, under conditions of iron limitation, a high-affinity siderophore, pyoverdine (PVD), which is recognized at the level of the outer membrane by a specific TonB-dependent receptor, FpvA. So far, for P. aeruginosa, three different PVDs, differing in their peptide chain, have been described (types I-III), but only the FpvA receptor for type I is known. Two PVD-producing P. aeruginosa strains, one type II and one type III, were mutagenized by a mini-TnphoA3 transposon. In each case, one mutant unable to grow in the presence of the strong iron chelator ethylenediaminedihydroxyphenylacetic acid (EDDHA) and the cognate PVD was selected. The first mutant, which had an insertion in the pvdE gene, upstream of fpvA, was unable to take up type II PVD and showed resistance to pyocin S3, which is known to use type II FpvA as receptor. The second mutant was unable to take up type III PVD and had the transposon insertion in fpvA. Cosmid libraries of the respective type II and type III PVD wild-type strains were constructed and screened for clones restoring the capacity to grow in the presence of PVD. From the respective complementing genomic fragments, type II and type III fpvA sequences were determined. When in trans, type II and type III fpvA restored PVD production, uptake, growth in the presence of EDDHA and, in the case of type II fpvA, pyocin S3 sensitivity. Complementation of fpvA mutants obtained by allelic exchange was achieved by the presence of cognate fpvA in trans. All three receptors posses an N-terminal extension of about 70 amino acids, similar to FecA of Escherichia coli, but only FpvAI has a TAT export sequence at its N-terminal end.

  6. Interleukin-1-receptor antagonist in type 2 diabetes mellitus

    Larsen, Claus M; Faulenbach, Mirjam; Vaag, Allan

    2007-01-01

    BACKGROUND: The expression of interleukin-1-receptor antagonist is reduced in pancreatic islets of patients with type 2 diabetes mellitus, and high glucose concentrations induce the production of interleukin-1beta in human pancreatic beta cells, leading to impaired insulin secretion, decreased cell...... proliferation, and apoptosis. METHODS: In this double-blind, parallel-group trial involving 70 patients with type 2 diabetes, we randomly assigned 34 patients to receive 100 mg of anakinra (a recombinant human interleukin-1-receptor antagonist) subcutaneously once daily for 13 weeks and 36 patients to receive...... placebo. At baseline and at 13 weeks, all patients underwent an oral glucose-tolerance test, followed by an intravenous bolus of 0.3 g of glucose per kilogram of body weight, 0.5 mg of glucagon, and 5 g of arginine. In addition, 35 patients underwent a hyperinsulinemic-euglycemic clamp study. The primary...

  7. Attenuated purinergic receptor function in patients with type 2 diabetes

    Thaning, Pia; Bune, Laurids T.; Hellsten, Ylva

    2010-01-01

    Objective: Extra cellular nucleotides and nucleosides are involved in regulation of skeletal muscle blood flow. Diabetes induces cardiovascular dysregulation but the extent to which the vasodilatatory capacity of nucleotides and nucleosides are affected in type 2 diabetes is unknown. The present...... study investigated: 1) the vasodilatatory effect of ATP, UTP, and adenosine (ADO) and 2) the expression and distribution of P2Y(2) and P2X(1) receptors in skeletal muscles of diabetic subjects. Research Design and Methods: In 10 diabetic patients and 10 age-matched controls, leg blood flow (LBF......-DM (1.5). The distribution and mRNA-expression of receptors were similar in the two groups. Conclusions: The vasodilatatory effect of the purinergic system is severely reduced in type 2 diabetic patients. The potency of nucleotides varies with the following rank order: UTP>ATP>>>ADO. This is not due...

  8. Structure and organization of heteromeric AMPA-type glutamate receptors.

    Herguedas, Beatriz; García-Nafría, Javier; Cais, Ondrej; Fernández-Leiro, Rafael; Krieger, James; Ho, Hinze; Greger, Ingo H

    2016-04-29

    AMPA-type glutamate receptors (AMPARs), which are central mediators of rapid neurotransmission and synaptic plasticity, predominantly exist as heteromers of the subunits GluA1 to GluA4. Here we report the first AMPAR heteromer structures, which deviate substantially from existing GluA2 homomer structures. Crystal structures of the GluA2/3 and GluA2/4 N-terminal domains reveal a novel compact conformation with an alternating arrangement of the four subunits around a central axis. This organization is confirmed by cysteine cross-linking in full-length receptors, and it permitted us to determine the structure of an intact GluA2/3 receptor by cryogenic electron microscopy. Two models in the ligand-free state, at resolutions of 8.25 and 10.3 angstroms, exhibit substantial vertical compression and close associations between domain layers, reminiscent of N-methyl-D-aspartate receptors. Model 1 resembles a resting state and model 2 a desensitized state, thus providing snapshots of gating transitions in the nominal absence of ligand. Our data reveal organizational features of heteromeric AMPARs and provide a framework to decipher AMPAR architecture and signaling. Copyright © 2016, American Association for the Advancement of Science.

  9. Multiple sleep alterations in mice lacking cannabinoid type 1 receptors.

    Alessandro Silvani

    Full Text Available Cannabinoid type 1 (CB1 receptors are highly expressed in the brain and play a role in behavior control. Endogenous cannabinoid signaling is modulated by high-fat diet (HFD. We investigated the consequences of congenital lack of CB1 receptors on sleep in mice fed standard diet (SD and HFD. CB1 cannabinoid receptor knock-out (KO and wild-type (WT mice were fed SD or HFD for 4 months (n = 9-10 per group. Mice were instrumented with electroencephalographic (EEG and electromyographic electrodes. Recordings were performed during baseline (48 hours, sleep deprivation (gentle handling, 6 hours, sleep recovery (18 hours, and after cage switch (insomnia model paradigm, 6 hours. We found multiple significant effects of genotype on sleep. In particular, KO spent more time awake and less time in non-rapid-eye-movement sleep (NREMS and rapid-eye-movement sleep (REMS than WT during the dark (active period but not during the light (rest period, enhancing the day-night variation of wake-sleep amounts. KO had slower EEG theta rhythm during REMS. REMS homeostasis after sleep deprivation was less effective in KO than in WT. Finally, KO habituated more rapidly to the arousing effect of the cage-switch test than WT. We did not find any significant effects of diet or of diet x genotype interaction on sleep. The occurrence of multiple sleep alterations in KO indicates important roles of CB1 cannabinoid receptors in limiting arousal during the active period of the day, in sleep regulation, and in sleep EEG in mice.

  10. DMPD: C-type lectin receptors in antifungal immunity. [Dynamic Macrophage Pathway CSML Database

    Full Text Available 18160296 C-type lectin receptors in antifungal immunity. Willment JA, Brown GD. Tre...nds Microbiol. 2008 Jan;16(1):27-32. Epub 2007 Dec 21. (.png) (.svg) (.html) (.csml) Show C-type lectin receptors in antifun...gal immunity. PubmedID 18160296 Title C-type lectin receptors in antifungal immunity. Author

  11. Tumor cell invasion of collagen matrices requires coordinate lipid agonist-induced G-protein and membrane-type matrix metalloproteinase-1-dependent signaling

    Anthis Nicholas J

    2006-12-01

    Full Text Available Abstract Background Lysophosphatidic acid (LPA and sphingosine 1-phosphate (S1P are bioactive lipid signaling molecules implicated in tumor dissemination. Membrane-type matrix metalloproteinase 1 (MT1-MMP is a membrane-tethered collagenase thought to be involved in tumor invasion via extracellular matrix degradation. In this study, we investigated the molecular requirements for LPA- and S1P-regulated tumor cell migration in two dimensions (2D and invasion of three-dimensional (3D collagen matrices and, in particular, evaluated the role of MT1-MMP in this process. Results LPA stimulated while S1P inhibited migration of most tumor lines in Boyden chamber assays. Conversely, HT1080 fibrosarcoma cells migrated in response to both lipids. HT1080 cells also markedly invaded 3D collagen matrices (~700 μm over 48 hours in response to either lipid. siRNA targeting of LPA1 and Rac1, or S1P1, Rac1, and Cdc42 specifically inhibited LPA- or S1P-induced HT1080 invasion, respectively. Analysis of LPA-induced HT1080 motility on 2D substrates vs. 3D matrices revealed that synthetic MMP inhibitors markedly reduced the distance (~125 μm vs. ~45 μm and velocity of invasion (~0.09 μm/min vs. ~0.03 μm/min only when cells navigated 3D matrices signifying a role for MMPs exclusively in invasion. Additionally, tissue inhibitors of metalloproteinases (TIMPs-2, -3, and -4, but not TIMP-1, blocked lipid agonist-induced invasion indicating a role for membrane-type (MT-MMPs. Furthermore, MT1-MMP expression in several tumor lines directly correlated with LPA-induced invasion. HEK293s, which neither express MT1-MMP nor invade in the presence of LPA, were transfected with MT1-MMP cDNA, and subsequently invaded in response to LPA. When HT1080 cells were seeded on top of or within collagen matrices, siRNA targeting of MT1-MMP, but not other MMPs, inhibited lipid agonist-induced invasion establishing a requisite role for MT1-MMP in this process. Conclusion LPA is a

  12. Molecular characterization of a novel human hybrid-type receptor that binds the alpha2-macroglobulin receptor-associated protein

    Jacobsen, Linda; Madsen, P; Moestrup, S K

    1996-01-01

    the corresponding cDNA. The gene, designated SORL1, maps to chromosome 11q 23/24 and encodes a 2214-residue type 1 receptor containing a furin cleavage site immediately preceding the N terminus determined in the purified protein. The receptor, designated sorLA-1, has a short cytoplasmic tail containing a tyrosine...... density lipoprotein receptor gene family receptors, and 3) six tandemly arranged fibronectin type III repeats also found in certain neural adhesion proteins. sorLA-1 may therefore be classified as a hybrid receptor. Northern blotting revealed specific mRNA transcripts in brain, spinal cord, and testis......The 39-40-kDa receptor-associated protein (RAP) binds to the members of the low density lipoprotein receptor gene family and functions as a specialized endoplasmic reticulum/Golgi chaperone. Using RAP affinity chromatography, we have purified a novel approximately 250-kDa brain protein and isolated...

  13. The future of type 1 cannabinoid receptor allosteric ligands.

    Alaverdashvili, Mariam; Laprairie, Robert B

    2018-02-01

    Allosteric modulation of the type 1 cannabinoid receptor (CB1R) holds great therapeutic potential. This is because allosteric modulators do not possess intrinsic efficacy, but instead augment (positive allosteric modulation) or diminish (negative allosteric modulation) the receptor's response to endogenous ligand. Consequently, CB1R allosteric modulators have an effect ceiling which allows for the tempering of CB1R signaling without the desensitization, tolerance, dependence, and psychoactivity associated with orthosteric compounds. Pain, movement disorders, epilepsy, obesity are all potential therapeutic targets for CB1R allosteric modulation. Several challenges exist for the development of CB1R allosteric modulators, such as receptor subtype specificity, translation to in vivo systems, and mixed allosteric/agonist/inverse agonist activity. Despite these challenges, elucidation of crystal structures of CB1R and compound design based on structure-activity relationships will advance the field. In this review, we will cover recent progress for CB1R allosteric modulators and discuss the future promise of this research.

  14. C-type Lectin Receptors for Tumor Eradication: Future Directions

    Streng-Ouwehand, Ingeborg; Unger, Wendy W. J.; Kooyk, Yvette van, E-mail: y.vankooyk@vumc.nl [Department of Molecular Cell Biology and Immunology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2011-08-08

    Dendritic cells are key regulators in directing immune responses and therefore are under extensive research for the induction of anti-tumor responses. DCs express a large array of receptors by which they scan their surroundings for recognition and uptake of pathogens. One of the receptor-families is the C-type lectins (CLR), which bind carbohydrate structures and internalize antigens upon recognition. Intracellular routing of antigen through CLR enhances loading and presentation of antigen through MHC class I and II, inducing antigen-specific CD4{sup +} and CD8{sup +} T-cell proliferation and skewing T-helper cells. These characteristics make CLRs very interesting targets for DC-based immunotherapy. Profound research has been done on targeting specific tumor antigens to CLR using either antibodies or the natural ligands such as glycan structures. In this review we will focus on the current data showing the potency of CLR-targeting and discuss improvements that can be achieved to enhance anti-tumor activity in the near future.

  15. Simvastatin enhances bone morphogenetic protein receptor type II expression

    Hu Hong; Sung, Arthur; Zhao, Guohua; Shi, Lingfang; Qiu Daoming; Nishimura, Toshihiko; Kao, Peter N.

    2006-01-01

    Statins confer therapeutic benefits in systemic and pulmonary vascular diseases. Bone morphogenetic protein (BMP) receptors serve essential signaling functions in cardiovascular development and skeletal morphogenesis. Mutations in BMP receptor type II (BMPR2) are associated with human familial and idiopathic pulmonary arterial hypertension, and pathologic neointimal proliferation of vascular endothelial and smooth muscle cells within small pulmonary arteries. In severe experimental pulmonary hypertension, simvastatin reversed disease and conferred a 100% survival advantage. Here, modulation of BMPR2 gene expression by simvastatin is characterized in human embryonic kidney (HEK) 293T, pulmonary artery smooth muscle, and lung microvascular endothelial cells (HLMVECs). A 1.4 kb BMPR2 promoter containing Egr-1 binding sites confers reporter gene activation in 293T cells which is partially inhibited by simvastatin. Simvastatin enhances steady-state BMPR2 mRNA and protein expression in HLMVEC, through posttranscriptional mRNA stabilization. Simvastatin induction of BMPR2 expression may improve BMP-BMPR2 signaling thereby enhancing endothelial differentiation and function

  16. Implications of compound heterozygous insulin receptor mutations in congenital muscle fibre type disproportion myopathy for the receptor kinase activation

    Klein, H H; Müller, R; Vestergaard, H

    1999-01-01

    We studied insulin receptor kinase activation in two brothers with congenital muscle fibre type disproportion myopathy and compound heterozygous mutations of the insulin receptor gene, their parents, and their unaffected brother. In the father who has a heterozygote Arg1174-->Gln mutation, in sit...

  17. Urokinase-type plasminogen activator receptor (uPAR), tissue factor (TF) and epidermal growth factor receptor (EGFR)

    Christensen, Anders; Kiss, Katalin; Lelkaitis, Giedrius

    2017-01-01

    Background: Tumor-specific biomarkers are a prerequisite for the development of targeted imaging and therapy in oral squamous cell carcinoma (OSCC). urokinase-type Plasminogen Activator Receptor (uPAR), Tissue Factor (TF) and Epidermal Growth Factor Receptor (EGFR) are three biomarkers that exhib...... with a reduced survival. uPAR seems to be a prognostic biomarker in oral cancer....

  18. Early double-negative thymocyte export in Trypanosoma cruzi infection is restricted by sphingosine receptors and associated with human chagas disease.

    Ailin Lepletier

    2014-10-01

    Full Text Available The protozoan parasite Trypanosoma cruzi is able to target the thymus and induce alterations of the thymic microenvironmental and lymphoid compartments. Acute infection results in severe atrophy of the organ and early release of immature thymocytes into the periphery. To date, the pathophysiological effects of thymic changes promoted by parasite-inducing premature release of thymocytes to the periphery has remained elusive. Herein, we show that sphingosine-1-phosphate (S1P, a potent mediator of T cell chemotaxis, plays a role in the exit of immature double-negative thymocytes in experimental Chagas disease. In thymuses from T. cruzi-infected mice we detected reduced transcription of the S1P kinase 1 and 2 genes related to S1P biosynthesis, together with increased transcription of the SGPL1 sphingosine-1-lyase gene, whose product inactivates S1P. These changes were associated with reduced intrathymic levels of S1P kinase activity. Interestingly, double-negative thymocytes from infected animals expressed high levels of the S1P receptor during infection, and migrated to lower levels of S1P. Moreover, during T. cruzi infection, this thymocyte subset expresses high levels of IL-17 and TNF-α cytokines upon polyclonal stimulation. In vivo treatment with the S1P receptor antagonist FTY720 resulted in recovery the numbers of double-negative thymocytes in infected thymuses to physiological levels. Finally, we showed increased numbers of double-negative T cells in the peripheral blood in severe cardiac forms of human Chagas disease.

  19. S1P1 receptor modulation preserves vascular function in mesenteric and coronary arteries after CPB in the rat independent of depletion of lymphocytes.

    Iryna V Samarska

    Full Text Available BACKGROUND: Cardiopulmonary bypass (CPB may induce systemic inflammation and vascular dysfunction. Sphingosine 1-phosphate (S1P modulates various vascular and immune responses. Here we explored whether agonists of the S1P receptors, FTY720 and SEW2871 improve vascular reactivity after CPB in the rat. METHODS: Experiments were done in male Wistar rats (total n = 127. Anesthesia was induced by isoflurane (2.5-3% and maintained by fentanyl and midazolam during CPB. After catheterization of the left femoral artery, carotid artery and the right atrium, normothermic extracorporeal circulation was instituted for 60 minutes. In the first part of the study animals were euthanized after either 1 hour, 1 day, 2 or 5 days of the recovery period. In second part of the study animals were euthanized after 1 day of postoperative period. We evaluated the contractile response to phenylephrine (mesenteric arteries or to serotonin (coronary artery and vasodilatory response to acethylcholine (both arteries. RESULTS: Contractile responses to phenylephrine were reduced at 1 day recovery after CPB and Sham as compared to healthy control animals (Emax, mN: 7.9 ± 1.9, 6.5 ± 1.5, and 11.3 ± 1.3, respectively. Mainly FTY720, but not SEW2871, caused lymphopenia in both Sham and CPB groups. In coronary and mesenteric arteries, both FTY720 and SEW2871 normalized serotonin and phenylephrine-mediated vascular reactivity after CPB (p<0.05 and FTY720 increased relaxation to acetylcholine as compared with untreated rats that underwent CPB. CONCLUSION: Pretreatment with FTY720 or SEW2871 preserves vascular function in mesenteric and coronary artery after CPB. Therefore, pharmacological activation of S1P1 receptors may provide a promising therapeutic intervention to prevent CPB-related vascular dysfunction in patients.

  20. Inactivation of the transforming growth factor beta type II receptor in human small cell lung cancer cell lines

    Hougaard, S; Nørgaard, P; Abrahamsen, N

    1999-01-01

    Transforming growth factor beta (TGF-beta) exerts a growth inhibitory effect on many cell types through binding to two types of receptors, the type I and II receptors. Resistance to TGF-beta due to lack of type II receptor (RII) has been described in some cancer types including small cell lung...

  1. Structural Analysis of Botulinum Neurotoxin Type G Receptor Binding

    Schmitt, John; Karalewitz, Andrew; Benefield, Desire A.; Mushrush, Darren J.; Pruitt, Rory N.; Spiller, Benjamin W.; Barbieri, Joseph T.; Lacy, D. Borden (Vanderbilt); (MCW)

    2010-10-19

    Botulinum neurotoxin (BoNT) binds peripheral neurons at the neuromuscular junction through a dual-receptor mechanism that includes interactions with ganglioside and protein receptors. The receptor identities vary depending on BoNT serotype (A-G). BoNT/B and BoNT/G bind the luminal domains of synaptotagmin I and II, homologous synaptic vesicle proteins. We observe conditions under which BoNT/B binds both Syt isoforms, but BoNT/G binds only SytI. Both serotypes bind ganglioside G{sub T1b}. The BoNT/G receptor-binding domain crystal structure provides a context for examining these binding interactions and a platform for understanding the physiological relevance of different Syt receptor isoforms in vivo.

  2. Serotonin type-1A receptor imaging in depression

    Drevets, Wayne C.; Frank, Ellen; Price, Julie C.; Kupfer, David J.; Greer, Phil J.; Mathis, Chester

    2000-01-01

    Regional 5-hydroxytryptamine 1A (5-HT 1A ) receptor binding potential (BP) of depressed subjects with primary, recurrent, familial mood disorders was compared to that of healthy controls by using positron emission tomography and [carbonyl- 11 C]WAY-100635 {[ 11 C]N-(2-(4-(2-methoxyphenyl)-1-piperazin-1-yl)ethyl)-N-(2-pyridyl) cyclohexanecarboxamide}. The mean 5-HT 1A receptor BP was reduced 42% in the midbrain raphe and 25-33% in limbic and neocortical areas in the mesiotemporal, occipital, and parietal cortex. The magnitude of these abnormalities was most prominent in bipolar depressives and unipolar depressives who had bipolar relatives. These abnormal reductions in 5-HT 1A receptor BP are consistent with in vivo evidence that 5-HT 1A receptor sensitivity is reduced in major depressive disorder and postmortem data showing a widespread deficit of 5-HT 1A receptor expression in primary mood disorders

  3. DMPD: Toll-like receptors and Type I interferons. [Dynamic Macrophage Pathway CSML Database

    Full Text Available m. 2007 May 25;282(21):15319-23. Epub 2007 Mar 29. (.png) (.svg) (.html) (.csml) Show Toll-like receptors and Type I interferons. Pub...medID 17395581 Title Toll-like receptors and Type I interferons. Authors Uematsu S,

  4. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor-delta

    Yan, Zhen Cheng; Liu, Dao Yan; Zhang, Li Li

    2007-01-01

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-delta (PPAR-delta)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow...... or a high-fat diet without and with regular endurance exercise. Exercise in rats on high-fat diet significantly reduced visceral fat mass, blood pressure, and adipocyte size (each p...

  5. DNA binding properties of dioxin receptors in wild-type and mutant mouse hepatoma cells

    Cuthill, S.; Poellinger, L.

    1988-01-01

    The current model of action of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) entails stimulation of target gene transcription via the formation of dioxin-receptor complexes and subsequent accumulation of the complexes within the cell nucleus. Here, the authors have analyzed the DNA binding properties of the dioxin receptor in wild-type mouse hepatoma (Hepa 1c1c7) cells and a class of nonresponsive mutant cells which fail to accumulate dioxin-receptor complexes within the nucleus in vivo. In vitro, both the wild-type and mutant [ 3 H]dioxin-receptor complexes exhibited low affinity for DNA-cellulose (5-8% and around 4% retention, respectively) in the absence of prior biochemical manipulations. However, following chromatography on heparin-Sepharose, the wild-type but not the mutant dioxin receptor was transformed to a species with an increased affinity for DNA (40-50% retention on DNA-cellulose). The gross molecular structure of the mutant, non DNA binding dioxin receptor did not appear to be altered as compared to that of the wild-type receptor. These results imply that the primary deficiency in the mutant dioxin receptor form may reside at the DNA binding level and that, in analogy to steroid hormone receptors, DNA binding of the receptor may be an essential step in the regulation of target gene transcription by dioxin

  6. Sigma-1 Receptor Plays a Negative Modulation on N-type Calcium Channel

    Kang Zhang

    2017-05-01

    Full Text Available The sigma-1 receptor is a 223 amino acids molecular chaperone with a single transmembrane domain. It is resident to eukaryotic mitochondrial-associated endoplasmic reticulum and plasma membranes. By chaperone-mediated interactions with ion channels, G-protein coupled receptors and cell-signaling molecules, the sigma-1 receptor performs broad physiological and pharmacological functions. Despite sigma-1 receptors have been confirmed to regulate various types of ion channels, the relationship between the sigma-1 receptor and N-type Ca2+ channel is still unclear. Considering both sigma-1 receptors and N-type Ca2+ channels are involved in intracellular calcium homeostasis and neurotransmission, we undertake studies to explore the possible interaction between these two proteins. In the experiment, we confirmed the expression of the sigma-1 receptors and the N-type calcium channels in the cholinergic interneurons (ChIs in rat striatum by using single-cell reverse transcription-polymerase chain reaction (scRT-PCR and immunofluorescence staining. N-type Ca2+ currents recorded from ChIs in the brain slice of rat striatum was depressed when sigma-1 receptor agonists (SKF-10047 and Pre-084 were administrated. The inhibition was completely abolished by sigma-1 receptor antagonist (BD-1063. Co-expression of the sigma-1 receptors and the N-type calcium channels in Xenopus oocytes presented a decrease of N-type Ca2+ current amplitude with an increase of sigma-1 receptor expression. SKF-10047 could further depress N-type Ca2+ currents recorded from oocytes. The fluorescence resonance energy transfer (FRET assays and co-immunoprecipitation (Co-IP demonstrated that sigma-1 receptors and N-type Ca2+ channels formed a protein complex when they were co-expressed in HEK-293T (Human Embryonic Kidney -293T cells. Our results revealed that the sigma-1 receptors played a negative modulation on N-type Ca2+ channels. The mechanism for the inhibition of sigma-1 receptors on

  7. Characterization of human endothelial cell urokinase-type plasminogen activator receptor protein and messenger RNA

    Barnathan, E S; Kuo, A; Karikó, K

    1990-01-01

    Human umbilical vein endothelial cells in culture (HUVEC) express receptors for urokinase-type plasminogen activators (u-PA). The immunochemical nature of this receptor and its relationship to u-PA receptors expressed by other cell types is unknown. Cross-linking active site-blocked u-PA to HUVEC...... an endothelial cell cDNA library using the polymerase chain reaction (PCR) and oligonucleotide primers corresponding to the DNA sequence of the receptor cloned from transformed human fibroblasts (Roldan et al, EMBO J 9:467, 1990). The size of the cDNA (approximately 1,054 base pairs, bp) and the presence...

  8. S1P lyase in thymic perivascular spaces promotes egress of mature thymocytes via up-regulation of S1P receptor 1.

    Maeda, Yasuhiro; Yagi, Hideki; Takemoto, Kana; Utsumi, Hiroyuki; Fukunari, Atsushi; Sugahara, Kunio; Masuko, Takashi; Chiba, Kenji

    2014-05-01

    Sphingosine 1-phosphate (S1P) and S1P receptor 1 (S1P1) play an important role in the egress of mature CD4 or CD8 single-positive (SP) thymocytes from the thymus. Fingolimod hydrochloride (FTY720), an S1P1 functional antagonist, induced significant accumulation of CD62L(high)CD69(low) mature SP thymocytes in the thymic medulla. Immunohistochemical staining using anti-S1P1 antibody revealed that S1P1 is predominantly expressed on thymocytes in the thymic medulla and is strongly down-regulated even at 3h after FTY720 administration. 2-Acetyl-4-tetrahydroxybutylimidazole (THI), an S1P lyase inhibitor, also induced accumulation of mature SP thymocytes in the thymic medulla with an enlargement of the perivascular spaces (PVS). At 6h after THI administration, S1P1-expressing thymocytes reduced partially as if to form clusters and hardly existed in the proximity of CD31-expressing blood vessels in the thymic medulla, suggesting S1P lyase expression in the cells constructing thymic medullary PVS. To determine the cells expressing S1P lyase in the thymus, we newly established a mAb (YK19-2) specific for mouse S1P lyase. Immunohistochemical staining with YK19-2 revealed that S1P lyase is predominantly expressed in non-lymphoid thymic stromal cells in the thymic medulla. In the thymic medullary PVS, S1P lyase was expressed in ER-TR7-positive cells (reticular fibroblasts and pericytes) and CD31-positive vascular endothelial cells. Our findings suggest that S1P lyase expressed in the thymic medullary PVS keeps the tissue S1P concentration low around the vessels and promotes thymic egress via up-regulation of S1P1.

  9. Mitigation of Initial Cardiodynamic Effects of the S1P1 Receptor Modulator Ponesimod Using a Novel Up-Titration Regimen.

    Juif, Pierre-Eric; Hoch, Matthias; Vaclavkova, Andrea; Krause, Andreas; Bush, Jim; Dingemanse, Jasper

    2017-03-01

    Ponesimod, a potent selective sphingosine-1-phosphate receptor 1 modulator, leads to a reduction in circulating total lymphocyte count and transient decreases in heart rate (HR). Based on a modeling and simulation approach, this study was conducted to investigate whether a gradual up-titration regimen may mitigate these cardiodynamic effects. In this double-blind, placebo-controlled, randomized, 2-way crossover study, 32 healthy participants (15 males) received placebo on day 1 followed by multiple-dose administration of either ponesimod or placebo (ratio 3:1). Ponesimod was administered alternately using regimen A (incremental dose increase from 2 to 20 mg in 9 steps) or B (10 mg for 7 days followed by a single-dose administration of 20 mg). Cardiodynamic (Holter and 12-lead ECG), pharmacokinetic, pharmacodynamic (total lymphocyte count), and safety variables were assessed. After first-dose ponesimod administration (day 2), a transient decrease in HR was observed (nadir 2-3 hours postdose, back to predose values within 4-5 hours) of approximately 6 and 12 beats/min (bpm) (mean) following regimens A and B, respectively. On day 2, occurrence of HR 20 ms, was lower following regimen A than B (14 vs 43 events). During the course of the study, incidence of HR <45 bpm was lower following regimen A than B (20 vs 58 events). Fewer participants reported adverse events following regimen A than B. Pharmacokinetics and pharmacodynamics were similar between the regimens. The novel gradual up-titration with ponesimod markedly mitigated initial cardiodynamic effects. © 2016, The American College of Clinical Pharmacology.

  10. The Pseudo signal peptide of the corticotropin-releasing factor receptor type 2A prevents receptor oligomerization.

    Teichmann, Anke; Rutz, Claudia; Kreuchwig, Annika; Krause, Gerd; Wiesner, Burkhard; Schülein, Ralf

    2012-08-03

    N-terminal signal peptides mediate the interaction of native proteins with the translocon complex of the endoplasmic reticulum membrane and are cleaved off during early protein biogenesis. The corticotropin-releasing factor receptor type 2a (CRF(2(a))R) possesses an N-terminal pseudo signal peptide, which represents a so far unique domain within the large protein family of G protein-coupled receptors (GPCRs). In contrast to a conventional signal peptide, the pseudo signal peptide remains uncleaved and consequently forms a hydrophobic extension at the N terminus of the receptor. The functional consequence of the presence of the pseudo signal peptide is not understood. Here, we have analyzed the significance of this domain for receptor dimerization/oligomerization in detail. To this end, we took the CRF(2(a))R and the homologous corticotropin-releasing factor receptor type 1 (CRF(1)R) possessing a conventional cleaved signal peptide and conducted signal peptide exchange experiments. Using single cell and single molecule imaging methods (fluorescence resonance energy transfer and fluorescence cross-correlation spectroscopy, respectively) as well as biochemical experiments, we obtained two novel findings; we could show that (i) the CRF(2(a))R is expressed exclusively as a monomer, and (ii) the presence of the pseudo signal peptide prevents its oligomerization. Thus, we have identified a novel functional domain within the GPCR protein family, which plays a role in receptor oligomerization and which may be useful to study the functional significance of this process in general.

  11. Impact of cell type and epitope tagging on heterologous expression of G protein-coupled receptor: a systematic study on angiotensin type II receptor.

    Lili Jiang

    Full Text Available Despite heterologous expression of epitope-tagged GPCR is widely adopted for functional characterization, there is lacking of systematic analysis of the impact of expression host and epitope tag on GPCR expression. Angiotensin type II (AT2 receptor displays agonist-dependent and -independent activities, coupling to a spectrum of signaling molecules. However, consensus has not been reached on the subcellular distributions, signaling cascades and receptor-mediated actions. To examine the contributions of host cell and epitope tag on receptor expression and activity, epitope-tagged AT2 receptor variants were transiently or stably expressed in HEK293, CHO-K1 and PC12 cells. The epitope-tagged AT2 receptor variants were detected both on the cell membrane and in the perinuclear region. In transiently transfected HEK293 cells, Myc-AT2 existed predominantly as monomer. Additionally, a ladder of ubiquitinated AT2 receptor proteins was detected. By contrast, stably expressed epitope-tagged AT2 receptor variants existed as both monomer and high molecular weight complexes, and the latter was enriched in cell surface. Glycosylation promoted cell surface expression of Myc-AT2 but had no effect on AT2-GFP in HEK293 cells. In cells that stably expressed Myc-AT2, serum starvation induced apoptosis in CHO-K1 cells but not in HEK293 or PC12 cells. Instead, HEK293 and PC12 cells stably expressing Myc-AT2 exhibited partial cell cycle arrest with cells accumulating at G1 and S phases, respectively. Taken together, these results suggest that expression levels, subcellular distributions and ligand-independent constitutive activities of AT2 receptor were cell type-dependent while posttranslational processing of nascent AT2 receptor protein was modulated by epitope tag and mode of expression.

  12. Serotonin type-1A receptor imaging in depression

    Drevets, Wayne C. E-mail: drevets@pet.upmc.edu; Frank, Ellen; Price, Julie C.; Kupfer, David J.; Greer, Phil J.; Mathis, Chester

    2000-07-01

    Regional 5-hydroxytryptamine{sub 1A} (5-HT{sub 1A}) receptor binding potential (BP) of depressed subjects with primary, recurrent, familial mood disorders was compared to that of healthy controls by using positron emission tomography and [carbonyl-{sup 11}C]WAY-100635 {l_brace}[{sup 11}C]N-(2-(4-(2-methoxyphenyl)-1-piperazin-1-yl)ethyl)-N-(2-pyridyl) cyclohexanecarboxamide{r_brace}. The mean 5-HT{sub 1A} receptor BP was reduced 42% in the midbrain raphe and 25-33% in limbic and neocortical areas in the mesiotemporal, occipital, and parietal cortex. The magnitude of these abnormalities was most prominent in bipolar depressives and unipolar depressives who had bipolar relatives. These abnormal reductions in 5-HT{sub 1A} receptor BP are consistent with in vivo evidence that 5-HT{sub 1A} receptor sensitivity is reduced in major depressive disorder and postmortem data showing a widespread deficit of 5-HT{sub 1A} receptor expression in primary mood disorders.

  13. Low density lipoprotein induces upregulation of vasoconstrictive endothelin type B receptor expression

    Xu, Cang-Bao; Zheng, Jian-Pu; Zhang, Wei

    2014-01-01

    Vasoconstrictive endothelin type B (ET(B)) receptors promote vasospasm and ischemic cerebro- and cardiovascular diseases. The present study was designed to examine if low density lipoprotein (LDL) induces upregulation of vasoconstrictive ET(B) receptor expression and if extracellular signal...

  14. Direct stimulation of angiotensin II type 2 receptor enhances spatial memory

    Jing, Fei; Mogi, Masaki; Sakata, Akiko

    2012-01-01

    We examined the possibility that direct stimulation of the angiotensin II type 2 (AT(2)) receptor by a newly generated direct AT(2) receptor agonist, Compound 21 (C21), enhances cognitive function. Treatment with C21 intraperitoneal injection for 2 weeks significantly enhanced cognitive function...

  15. Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor

    Chávez-Vargas, Lydia; Adame-García, Sendi Rafael; Cervantes-Villagrana, Rodolfo Daniel; Castillo-Kauil, Alejandro; Bruystens, Jessica G. H.; Fukuhara, Shigetomo; Taylor, Susan S.; Mochizuki, Naoki; Reyes-Cruz, Guadalupe; Vázquez-Prado, José

    2016-01-01

    Morphology of migrating cells is regulated by Rho GTPases and fine-tuned by protein interactions and phosphorylation. PKA affects cell migration potentially through spatiotemporal interactions with regulators of Rho GTPases. Here we show that the endogenous regulatory (R) subunit of type I PKA interacts with P-Rex1, a Rac guanine nucleotide exchange factor that integrates chemotactic signals. Type I PKA holoenzyme interacts with P-Rex1 PDZ domains via the CNB B domain of RIα, which when expressed by itself facilitates endothelial cell migration. P-Rex1 activation localizes PKA to the cell periphery, whereas stimulation of PKA phosphorylates P-Rex1 and prevents its activation in cells responding to SDF-1 (stromal cell-derived factor 1). The P-Rex1 DEP1 domain is phosphorylated at Ser-436, which inhibits the DH-PH catalytic cassette by direct interaction. In addition, the P-Rex1 C terminus is indirectly targeted by PKA, promoting inhibitory interactions independently of the DEP1-PDZ2 region. A P-Rex1 S436A mutant construct shows increased RacGEF activity and prevents the inhibitory effect of forskolin on sphingosine 1-phosphate-dependent endothelial cell migration. Altogether, these results support the idea that P-Rex1 contributes to the spatiotemporal localization of type I PKA, which tightly regulates this guanine exchange factor by a multistep mechanism, initiated by interaction with the PDZ domains of P-Rex1 followed by direct phosphorylation at the first DEP domain and putatively indirect regulation of the C terminus, thus promoting inhibitory intramolecular interactions. This reciprocal regulation between PKA and P-Rex1 might represent a key node of integration by which chemotactic signaling is fine-tuned by PKA. PMID:26797121

  16. Peripheral-type benzodiazepine receptor: a protein of mitochondrial outer membranes utilizing porphyrins as endogenous ligands

    Snyder, S.H.; Verma, A.; Trifiletti, R.R.

    1987-01-01

    The peripheral-type benzodiazepine receptor is a site identified by its nanomolar affinity for [ 3 H]diazepam, similar to the affinity of diazepam for the central-type benzodiazepine receptor in the brain. The peripheral type benzodiazepine receptor occurs in many peripheral tissues but has discrete localizations as indicated by autoradiographic studies showing uniquely high densities of the receptors in the adrenal cortex and in Leydig cells of the testes. Subcellular localization studies reveal a selective association of the receptors with the outer membrane of mitochondria. Photoaffinity labeling of the mitochondrial receptor with [ 3 H]flunitrazepam reveals two discrete labeled protein bands of 30 and 35 kDa, respectively. The 35-kDa band appears to be identical with the voltage-dependent anion channel protein porin. Fractionation of numerous peripheral tissues reveals a single principal endogenous ligand for the receptor, consisting of porphyrins, which display nanomolar affinity. Interactions of porphyrins with the mitochondrial receptor may clarify its physiological role and account for many pharmacological actions of benzodiazepines

  17. Effects of muscarinic receptor antagonists on cocaine discrimination in wild-type mice and in muscarinic receptor M1, M2, and M4 receptor knockout mice.

    Joseph, Lauren; Thomsen, Morgane

    2017-06-30

    Muscarinic M 1 /M 4 receptor stimulation can reduce abuse-related effects of cocaine and may represent avenues for treating cocaine addiction. Muscarinic antagonists can mimic and enhance effects of cocaine, including discriminative stimulus (S D ) effects, but the receptor subtypes mediating those effects are not known. A better understanding of the complex cocaine/muscarinic interactions is needed to evaluate and develop potential muscarinic-based medications. Here, knockout mice lacking M 1 , M 2 , or M 4 receptors (M 1 -/- , M 2 -/- , M 4 -/- ), as well as control wild-type mice and outbred Swiss-Webster mice, were trained to discriminate 10mg/kg cocaine from saline. Muscarinic receptor antagonists with no subtype selectivity (scopolamine), or preferential affinity at the M 1 , M 2 , or M 4 subtype (telenzepine, trihexyphenidyl; methoctramine, AQ-RA 741; tropicamide) were tested alone and in combination with cocaine. In intact animals, antagonists with high affinity at M 1 /M 4 receptors partially substituted for cocaine and increased the S D effect of cocaine, while M 2 -preferring antagonists did not substitute, and reduced the S D effect of cocaine. The cocaine-like effects of scopolamine were absent in M 1 -/- mice. The cocaine S D attenuating effects of methoctramine were absent in M 2 -/- mice and almost absent in M 1 -/- mice. The findings indicate that the cocaine-like S D effects of muscarinic antagonists are primarily mediated through M 1 receptors, with a minor contribution of M 4 receptors. The data also support our previous findings that stimulation of M 1 receptors and M 4 receptors can each attenuate the S D effect of cocaine, and show that this can also be achieved by blocking M 2 autoreceptors, likely via increased acetylcholine release. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Angiotensin II Type 2 Receptor and Receptor Mas Are Colocalized and Functionally Interdependent in Obese Zucker Rat Kidney

    Patel, Sanket N; Ali, Quaisar; Samuel, Preethi

    2017-01-01

    The actions of angiotensin II type 2 receptor (AT2R) and the receptor Mas (MasR) are complex but show similar pronatriuretic function; particularly, AT2R expression and natriuretic function are enhanced in obese/diabetic rat kidney. In light of some reports suggesting a potential positive...... interaction between these receptors, we tested hypothesis that renal AT2R and MasR physically interact and are interdependent to stimulate cell signaling and promote natriuresis in obese rats. We found that infusion of AT2R agonist C21 in obese Zucker rats (OZR) increased urine flow and urinary Na excretion...... coimmunoprecipitated with MasR in cortical homogenate of OZR. Immunoblotting of cortical homogenate cross-linked with zero-length oxidative (sulfhydryl groups) cross-linker cupric-phenanthroline revealed a shift of AT2R and MasR bands upward with overlapping migration for their complexes which were sensitive...

  19. Reduced post-synaptic serotonin type 1A receptor binding in bipolar depression

    Nugent, Allison C.; Bain, Earle E.; Carlson, Paul J.; Neumeister, Alexander; Bonne, Omer; Carson, Richard E.; Eckelman, William; Herscovitch, Peter; Zarate, Carlos A.; Charney, Dennis S.; Drevets, Wayne C.

    2013-01-01

    Multiple lines of evidence suggest that serotonin type 1A (5-HT1A) receptor dysfunction is involved in the pathophysiology of mood disorders, and that alterations in 5-HT1A receptor function play a role in the mechanisms of antidepressant and mood stabilizer treatment. The literature is in disagreement, however, as to whether 5-HT1A receptor binding abnormalities exist in bipolar disorder (BD). We acquired PET images of 5-HT1A receptor binding in 26 unmedicated BD subjects and 37 healthy controls using [18F]FCWAY, a highly selective 5-HT1A receptor radio-ligand. The mean 5-HT1A receptor binding potential (BPP) was significantly lower in BD subjects compared to controls in cortical regions where 5-HT1A receptors are expressed post-synaptically, most prominently in the mesiotemporal cortex. Post-hoc assessments involving other receptor specific binding parameters suggested that this difference particularly affected the females with BD. The mean BPP did not differ between groups in the raphe nucleus, however, where 5-HT1A receptors are predominantly expressed pre-synaptically. Across subjects the BPP in the mesiotemporal cortex was inversely correlated with trough plasma cortisol levels, consistent with preclinical literature indicating that hippocampal 5-HT1A receptor expression is inhibited by glucocorticoid receptor stimulation. These findings suggest that 5-HT1A receptor binding is abnormally reduced in BD, and this abnormality may particularly involve the postsynaptic 5-HT1A receptor system of individuals with a tendency toward cortisol hypersecretion. PMID:23434290

  20. beta-Arrestin 1 and 2 stabilize the angiotensin II type I receptor in distinct high-affinity conformations

    Sanni, S J; Hansen, J T; Bonde, M M

    2010-01-01

    The angiotensin II type 1 (AT(1)) receptor belongs to family A of 7 transmembrane (7TM) receptors. The receptor has important roles in the cardiovascular system and is commonly used as a drug target in cardiovascular diseases. Interaction of 7TM receptors with G proteins or beta-arrestins often...

  1. The Vasopressin Type-2 Receptor and Prostaglandin Receptors EP2 and EP4 can Increase Aquaporin-2 Plasma Membrane Targeting Through a cAMP Independent Pathway

    Olesen, Emma Tina Bisgaard; Moeller, Hanne Bjerregaard; Assentoft, Mette

    2016-01-01

    Apical membrane targeting of the collecting duct water channel aquaporin-2 (AQP2) is essential for body water balance. As this event is regulated by Gs coupled 7-transmembrane receptors such as the vasopressin type 2 receptor (V2R) and the prostanoid receptors EP2 and EP4, it is believed to be c...

  2. Differential Effects of Long Term FTY720 Treatment on Endothelial versus Smooth Muscle Cell Signaling to S1P in Rat Mesenteric Arteries

    Shishavan, Mahdi Hamidi; Bidadkosh, Arash; Yazdani, Saleh; Lambooy, Sebastiaan; van den Born, Jacob; Buikema, Hendrik; Henning, Robert H.; Deelman, Leo E.

    2016-01-01

    The sphingosine-1-phosphate (S1P) analog FTY720 exerts pleiotropic effects on the cardiovascular system and causes down-regulation of S1P receptors. Myogenic constriction is an important mechanism regulating resistance vessel function and is known to be modulated by S1P. Here we investigated

  3. Oral fingolimod (FTY720) in multiple sclerosis: two-year results of a phase II extension study

    O'Connor, P; Comi, G; Montalban, X

    2009-01-01

    OBJECTIVE: To report the results of a 24-month extension of a phase II trial assessing the efficacy, safety, and tolerability of the once-daily oral sphingosine-1-phosphate receptor modulator, fingolimod (FTY720), in relapsing multiple sclerosis (MS). METHODS: In the randomized, double-blind, pla...

  4. FTY720 on the way from the base camp to the summit of the mountain: relevance for remyelination

    Kipp, M.; Amor, S.

    2012-01-01

    FTY720 (fingolimod; Gilenya®), a sphingosine 1-phosphate (S1P) receptor modulator, is the first oral disease-modifying therapy to be approved for the treatment of relapsing-remitting multiple sclerosis. FTY720 is rapidly converted in vivo to the active S-fingolimod-phosphate, which binds to S1P

  5. β-arrestins negatively control human adrenomedullin type 1-receptor internalization

    Kuwasako, Kenji; Kitamura, Kazuo; Nagata, Sayaka; Sekiguchi, Toshio; Danfeng, Jiang; Murakami, Manabu; Hattori, Yuichi; Kato, Johji

    2017-01-01

    Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM 1 receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM 1 receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β 2 -adrenergic receptor (β 2 -AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [ 125 I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM 1 receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM 1 receptor internalization. In contrast, the AM-induced internalization of the chimeric AM 1 receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β 2 -AR. Thus, both β-arrs negatively control AM 1 receptor internalization, which depends on the C-tail of CLR. - Highlights: • We found that β-arrestins 1 and 2 negatively control agonist-induced GPCR internalization. • β-arrestins 1 and 2 significantly inhibits the AM

  6. β-arrestins negatively control human adrenomedullin type 1-receptor internalization.

    Kuwasako, Kenji; Kitamura, Kazuo; Nagata, Sayaka; Sekiguchi, Toshio; Danfeng, Jiang; Murakami, Manabu; Hattori, Yuichi; Kato, Johji

    2017-05-27

    Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM 1 receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM 1 receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β 2 -adrenergic receptor (β 2 -AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [ 125 I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM 1 receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM 1 receptor internalization. In contrast, the AM-induced internalization of the chimeric AM 1 receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β 2 -AR. Thus, both β-arrs negatively control AM 1 receptor internalization, which depends on the C-tail of CLR. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Activating and deactivating mutations in the receptor interaction site of GDF5 cause symphalangism or brachydactyly type A2

    Seemann, Petra; Schwappacher, Raphaela; Kjær, Klaus Wilbrandt

    2005-01-01

    Here we describe 2 mutations in growth and differentiation factor 5 (GDF5) that alter receptor-binding affinities. They cause brachydactyly type A2 (L441P) and symphalangism (R438L), conditions previously associated with mutations in the GDF5 receptor bone morphogenetic protein receptor type 1b...

  8. Human Complement Receptor Type 1/CD35 Is an Epstein-Barr Virus Receptor

    Javier G. Ogembo

    2013-02-01

    Full Text Available Epstein-Barr virus (EBV attachment to primary B cells initiates virus entry. Although CD21 is the only known receptor for EBVgp350/220, a recent report documents EBV-infected B cells from a patient genetically deficient in CD21. On normal resting B cells, CD21 forms two membrane complexes: one with CD19 and another with CD35. Whereas the CD21/CD19 complex is widely retained on immortalized and B cell tumor lines, the related complement-regulatory protein CD35 is lost. To determine the role(s of CD35 in initial infection, we transduced a CD21-negative pre-B cell and myeloid leukemia line with CD35, CD21, or both. Cells expressing CD35 alone bound gp350/220 and became latently infected when the fusion receptor HLA II was coexpressed. Temporal, biophysical, and structural characteristics of CD35-mediated infection were distinct from CD21. Identification of CD35 as an EBV receptor uncovers a salient role in primary infection, addresses unsettled questions of virus tropism, and underscores the importance of EBVgp350/220 for vaccine development.

  9. Peripheral-type benzodiazepine receptors in the central nervous system: localization to olfactory nerves.

    Anholt, R R; Murphy, K M; Mack, G E; Snyder, S H

    1984-02-01

    Binding levels of [3H]Ro5-4864, a ligand selective for peripheral-type benzodiazepine receptors, are substantially higher in homogenates of the olfactory bulb than in the rest of the brain. Among peripheral tissues evaluated, high levels of [3H]Ro5-4864 binding are found in the nasal epithelium. Drug displacement studies show that these binding sites are pharmacologically of the peripheral type. Their presence in the nasal epithelium and in the olfactory bulb can be demonstrated in several different mammalian species. Autoradiographic studies of murine nose reveal a bipolar staining pattern around the cell bodies of the olfactory receptor cells, suggesting the presence of peripheral-type benzodiazepine receptors on both processes of these bipolar neurons. In the brain a high density of [3H]Ro5-4864 binding sites occurs in the nerve fiber and glomerular layers of the olfactory bulb. Throughout the rest of the brain [3H]Ro5-4864-associated silver grains are diffusely distributed with intense staining over the choroid plexus and along the ependymal linings of the ventricles. Both the distribution and the ontogenic development of the peripheral-type benzodiazepine receptors differ from the central-type receptors. Intranasal irrigation with 5% ZnSO4 results in a 50% reduction of peripheral-type benzodiazepine receptors in the olfactory bulb without affecting the density of central-type benzodiazepine receptors. Thus, [3H]Ro5-4864 binding sites in the olfactory bulb appear in large part to be localized to olfactory nerves which originate in the nasal epithelium.

  10. Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor: EFFECT ON PKA LOCALIZATION AND P-Rex1 SIGNALING.

    Chávez-Vargas, Lydia; Adame-García, Sendi Rafael; Cervantes-Villagrana, Rodolfo Daniel; Castillo-Kauil, Alejandro; Bruystens, Jessica G H; Fukuhara, Shigetomo; Taylor, Susan S; Mochizuki, Naoki; Reyes-Cruz, Guadalupe; Vázquez-Prado, José

    2016-03-18

    Morphology of migrating cells is regulated by Rho GTPases and fine-tuned by protein interactions and phosphorylation. PKA affects cell migration potentially through spatiotemporal interactions with regulators of Rho GTPases. Here we show that the endogenous regulatory (R) subunit of type I PKA interacts with P-Rex1, a Rac guanine nucleotide exchange factor that integrates chemotactic signals. Type I PKA holoenzyme interacts with P-Rex1 PDZ domains via the CNB B domain of RIα, which when expressed by itself facilitates endothelial cell migration. P-Rex1 activation localizes PKA to the cell periphery, whereas stimulation of PKA phosphorylates P-Rex1 and prevents its activation in cells responding to SDF-1 (stromal cell-derived factor 1). The P-Rex1 DEP1 domain is phosphorylated at Ser-436, which inhibits the DH-PH catalytic cassette by direct interaction. In addition, the P-Rex1 C terminus is indirectly targeted by PKA, promoting inhibitory interactions independently of the DEP1-PDZ2 region. A P-Rex1 S436A mutant construct shows increased RacGEF activity and prevents the inhibitory effect of forskolin on sphingosine 1-phosphate-dependent endothelial cell migration. Altogether, these results support the idea that P-Rex1 contributes to the spatiotemporal localization of type I PKA, which tightly regulates this guanine exchange factor by a multistep mechanism, initiated by interaction with the PDZ domains of P-Rex1 followed by direct phosphorylation at the first DEP domain and putatively indirect regulation of the C terminus, thus promoting inhibitory intramolecular interactions. This reciprocal regulation between PKA and P-Rex1 might represent a key node of integration by which chemotactic signaling is fine-tuned by PKA. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Cannabinoid receptor type-1: breaking the dogmas [version 1; referees: 3 approved

    Arnau Busquets Garcia

    2016-05-01

    Full Text Available The endocannabinoid system (ECS is abundantly expressed in the brain. This system regulates a plethora of physiological functions and is composed of cannabinoid receptors, their endogenous ligands (endocannabinoids, and the enzymes involved in the metabolism of endocannabinoids. In this review, we highlight the new advances in cannabinoid signaling, focusing on a key component of the ECS, the type-1 cannabinoid receptor (CB1. In recent years, the development of new imaging and molecular tools has demonstrated that this receptor can be distributed in many cell types (e.g., neuronal or glial cells and intracellular compartments (e.g., mitochondria. Interestingly, cellular and molecular effects are differentially mediated by CB1 receptors according to their specific localization (e.g., glutamatergic or GABAergic neurons. Moreover, this receptor is expressed in the periphery, where it can modulate periphery-brain connections. Finally, the better understanding of the CB1 receptor structure led researchers to propose interesting and new allosteric modulators. Thus, the advances and the new directions of the CB1 receptor field will provide new insights and better approaches to profit from its interesting therapeutic profile.

  12. Upregulation of Cannabinoid Type 1 Receptors in Dopamine D2 Receptor Knockout Mice Is Reversed by Chronic Forced Ethanol Consumption

    Thanos, P.K.; Wang, G.; Thanos, P.K.; Gopez, V.; Delis, F.; Michaelides, M.; Grand, D.K.; Wang, G.-J.; Kunos, G.; Volkow, N.D.

    2011-01-01

    The anatomical proximity of the cannabinoid type 1 (CNR1/CB1R) and the dopamine D2 receptors (DRD2), their ability to form CB1R-DRD2 heteromers, their opposing roles in locomotion, and their involvement in ethanol's reinforcing and addictive properties prompted us to study the levels and distribution of CB1R after chronic ethanol intake, in the presence and absence of DRD2. We monitored the drinking patterns and locomotor activity of Drd2+/+ and Drd2-/- mice consuming either water or a 20% (v/v) ethanol solution (forced ethanol intake) for 6 months and used the selective CB1 receptor antagonist [{sup 3}H]SR141716A to quantify CB1R levels in different brain regions with in vitro receptor autoradiography. We found that the lack of DRD2 leads to a marked upregulation (approximately 2-fold increase) of CB1R in the cerebral cortex, the caudate-putamen, and the nucleus accumbens, which was reversed by chronic ethanol intake. The results suggest that DRD2-mediated dopaminergic neurotransmission and chronic ethanol intake exert an inhibitory effect on cannabinoid receptor expression in cortical and striatal regions implicated in the reinforcing and addictive properties of ethanol.

  13. Role of σ1 Receptors in Learning and Memory and Alzheimer's Disease-Type Dementia.

    Maurice, Tangui; Goguadze, Nino

    2017-01-01

    The present chapter will review the role of σ 1 receptor in learning and memory and neuroprotection , against Alzheimer's type dementia. σ 1 Receptor agonists have been tested in a variety of pharmacological and pathological models of learning impairments in rodents these last past 20 years. Their anti-amnesic effects have been explained by the wide-range modulatory role of σ 1 receptors on Ca 2+ mobilizations, neurotransmitter responses, and particularly glutamate and acetylcholine systems, and neurotrophic factors. Recent observations from genetic and pharmacological studies have shown that σ 1 receptor can also be targeted in neurodegenerative diseases, and particularly Alzheimer's disease . Several compounds, acting partly through the σ 1 receptor, have showed effective neuroprotection in transgenic mouse models of Alzheimer's disease . We will review the data and discuss the possible mechanisms of action, particularly focusing on oxidative stress and mitochondrial integrity, trophic factors and a novel hypothesis suggesting a functional interaction between the σ 1 receptor and α 7 nicotinic acetylcholine receptor. Finally, we will discuss the pharmacological peculiarities of non-selective σ 1 receptor ligands, now developed as neuroprotectants in Alzheimer's disease , and positive modulators, recently described and that showed efficacy against learning and memory deficits.

  14. Expression of S1P metabolizing enzymes and receptors correlate with survival time and regulate cell migration in glioblastoma multiforme.

    Bien-Möller, Sandra; Lange, Sandra; Holm, Tobias; Böhm, Andreas; Paland, Heiko; Küpper, Johannes; Herzog, Susann; Weitmann, Kerstin; Havemann, Christoph; Vogelgesang, Silke; Marx, Sascha; Hoffmann, Wolfgang; Schroeder, Henry W S; Rauch, Bernhard H

    2016-03-15

    A signaling molecule which is involved in proliferation and migration of malignant cells is the lipid mediator sphingosine-1-phosphate (S1P). There are hints for a potential role of S1P signaling in malignant brain tumors such as glioblastoma multiforme (GBM) which is characterized by a poor prognosis. Therefore, a comprehensive expression analysis of S1P receptors (S1P1-S1P5) and S1P metabolizing enzymes in human GBM (n = 117) compared to healthy brain (n = 10) was performed to evaluate their role for patient´s survival. Furthermore, influence of S1P receptor inhibition on proliferation and migration were studied in LN18 GBM cells. Compared to control brain, mRNA levels of S1P1, S1P2, S1P3 and S1P generating sphingosine kinase-1 were elevated in GBM. Kaplan-Meier analyses demonstrated an association between S1P1 and S1P2 with patient´s survival times. In vitro, an inhibitory effect of the SphK inhibitor SKI-II on viability of LN18 cells was shown. S1P itself had no effect on viability but stimulated LN18 migration which was blocked by inhibition of S1P1 and S1P2. The participation of S1P1 and S1P2 in LN18 migration was further supported by siRNA-mediated silencing of these receptors. Immunoblots and inhibition experiments suggest an involvement of the PI3-kinase/AKT1 pathway in the chemotactic effect of S1P in LN18 cells.In summary, our data argue for a role of S1P signaling in proliferation and migration of GBM cells. Individual components of the S1P pathway represent prognostic factors for patients with GBM. Perspectively, a selective modulation of S1P receptor subtypes could represent a therapeutic approach for GBM patients and requires further evaluation.

  15. Macrophage-to-sensory neuron crosstalk mediated by Angiotensin II type-2 receptor elicits neuropathic pain

    Krause, Eric; Shepherd, Andrew; Mickle, Aaron; Copits, Bryan; Karlsson, Pall; Kadunganattil, Suraj; Golden, Judith; Tadinada, Satya; Mack, Madison; Haroutounian, Simon; De Kloet, Annette; Samineni, Vijay; Valtcheva, Manouela; Mcilvried, Lisa; Sheahan, Tayler

    2017-01-01

    Peripheral nerve damage initiates a complex series of cellular and structural processes that culminate in chronic neuropathic pain. Our study defines local angiotensin signaling via activation of the Angiotensin II (Ang II) type-2 receptor (AT2R) on macrophages as the critical trigger of neuropathic pain. An AT2R-selective antagonist attenuates neuropathic, but not inflammatory pain hypersensitivity in mice, and requires the cell damage-sensing ion channel transient receptor potential family-...

  16. Increased expression of vascular endothelin type B and angiotensin type 1 receptors in patients with ischemic heart disease

    Dimitrijevic, Ivan; Edvinsson, Lars; Chen, Qingwen

    2009-01-01

    expression in subcutaneous arteries from patients with different degrees of ischemic heart disease. METHODS: Subcutaneous arteries were obtained, by biopsy from the abdomen, from patients undergoing coronary artery bypass graft (CABG) surgery because of ischemic heart disease (n = 15), patients with angina...... pectoris without established myocardial infarction (n = 15) and matched cardiovascular healthy controls (n = 15). Endothelin type A (ETA) and type B (ETB), and angiotensin type 1 (AT1) and type 2 (AT2) receptors expression and function were examined using immunohistochemistry, Western blot and in vitro...

  17. Therapeutic targeting of angiotensin II receptor type 1 to regulate androgen receptor in prostate cancer.

    Takahashi, Satoru; Uemura, Hiroji; Seeni, Azman; Tang, Mingxi; Komiya, Masami; Long, Ne; Ishiguro, Hitoshi; Kubota, Yoshinobu; Shirai, Tomoyuki

    2012-10-01

    With the limited strategies for curative treatment of castration-resistant prostate cancer (CRPC), public interest has focused on the potential prevention of prostate cancer. Recent studies have demonstrated that an angiotensin II receptor blocker (ARB) has the potential to decrease serum prostate-specific antigen (PSA) level and improve performance status in CRPC patients. These facts prompted us to investigate the direct effects of ARBs on prostate cancer growth and progression. Transgenic rat for adenocarcinoma of prostate (TRAP) model established in our laboratory was used. TRAP rats of 3 weeks of age received ARB (telmisartan or candesartan) at the concentration of 2 or 10 mg/kg/day in drinking water for 12 weeks. In vitro analyses for cell growth, ubiquitylation or reporter gene assay were performed using LNCaP cells. We found that both telmisartan and candesartan attenuated prostate carcinogenesis in TRAP rats by augmentation of apoptosis resulting from activation of caspases, inactivation of p38 MAPK and down-regulation of the androgen receptor (AR). Further, microarray analysis demonstrated up-regulation of estrogen receptor β (ERβ) by ARB treatment. In both parental and androgen-independent LNCaP cells, ARB inhibited both cell growth and AR-mediated transcriptional activity. ARB also exerted a mild additional effect on AR-mediated transcriptional activation by the ERβ up-regulation. An intervention study revealed that PSA progression was prolonged in prostate cancer patients given an ARB compared with placebo control. These data provide a new concept that ARBs are promising potential chemopreventive and chemotherapeutic agents for prostate cancer. Copyright © 2012 Wiley Periodicals, Inc.

  18. Expression of Dihydropyridine and Ryanodine Receptors in Type IIA Fibers of Rat Skeletal Muscle

    Anttila, Katja; Mänttäri, Satu; Järvilehto, Matti

    2007-01-01

    In this study, the fiber type specificity of dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs) in different rat limb muscles was investigated. Western blot and histochemical analyses provided for the first time evidence that the expression of both receptors correlates to a specific myosin heavy chain (MHC) composition. We observed a significant (p=0.01) correlation between DHP as well as Ry receptor density and the expression of MHC IIa (correlation factor r=0.674 and r=0.645, respectively) in one slow-twitch, postural muscle (m. soleus), one mixed, fast-twitch muscle (m. gastrocnemius) and two fast-twitch muscles (m. rectus femoris, m. extensor digitorum longus). The highest DHP and Ry receptor density was found in the white part of m. rectus femoris (0.058±0.0060 and 0.057±0.0158 ODu, respectively). As expected, the highest relative percentage of MHC IIa was also found in the white part of m. rectus femoris (70.0±7.77%). Furthermore, histochemical experiments revealed that the IIA fibers stained most strongly for the fluorophore-conjugated receptor blockers. Our data clearly suggest that the expression of DHPRs and RyRs follows a fiber type-specific pattern, indicating an important role for these proteins in the maintenance of an effective Ca 2+ cycle in the fast contracting fiber type IIA

  19. Regulation of S1P receptors and sphingosine kinases expression in acute pulmonary endothelial cell injury

    Huiying Liu

    2016-12-01

    Full Text Available Background Acute lung injury and acute respiratory distress syndrome (ALI/ARDS is a severe clinical syndrome with mortality rate as high as 30–40%. There is no treatment yet to improve pulmonary endothelial barrier function in patients with severe pulmonary edema. Developing therapies to protect endothelial barrier integrity and stabilizing gas exchange is getting more and more attention. Sphingosine-1-phosphate (S1P is able to enhance the resistance of endothelial cell barrier. S1P at physiological concentrations plays an important role in maintaining endothelial barrier function. Proliferation, regeneration and anti-inflammatory activity that mesenchymal stem cells (MSCs exhibit make it possible to regulate the homeostatic control of S1P. Methods By building a pulmonary endothelial cell model of acute injury, we investigated the regulation of S1P receptors and sphingosine kinases expression by MSCs during the treatment of acute lung injury using RT-PCR, and investigated the HPAECs Micro-electronics impedance using Real Time Cellular Analysis. Results It was found that the down-regulation of TNF-α expression was more significant when MSC was used in combination with S1P. The combination effection mainly worked on S1PR2, S1PR3 and SphK2. The results show that when MSCs were used in combination with S1P, the selectivity of S1P receptors was increased and the homeostatic control of S1P concentration was improved through regulation of expression of S1P metabolic enzymes. Discussions The study found that, as a potential treatment, MSCs could work on multiple S1P related genes simultaneously. When it was used in combination with S1P, the expression regulation result of related genes was not simply the superposition of each other, but more significant outcome was obtained. This study establishes the experimental basis for further exploring the efficacy of improving endothelial barrier function in acute lung injury, using MSCs in combination with S1

  20. Regulation of S1P receptors and sphingosine kinases expression in acute pulmonary endothelial cell injury.

    Liu, Huiying; Zhang, Zili; Li, Puyuan; Yuan, Xin; Zheng, Jing; Liu, Jinwen; Bai, Changqing; Niu, Wenkai

    2016-01-01

    Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) is a severe clinical syndrome with mortality rate as high as 30-40%. There is no treatment yet to improve pulmonary endothelial barrier function in patients with severe pulmonary edema. Developing therapies to protect endothelial barrier integrity and stabilizing gas exchange is getting more and more attention. Sphingosine-1-phosphate (S1P) is able to enhance the resistance of endothelial cell barrier. S1P at physiological concentrations plays an important role in maintaining endothelial barrier function. Proliferation, regeneration and anti-inflammatory activity that mesenchymal stem cells (MSCs) exhibit make it possible to regulate the homeostatic control of S1P. By building a pulmonary endothelial cell model of acute injury, we investigated the regulation of S1P receptors and sphingosine kinases expression by MSCs during the treatment of acute lung injury using RT-PCR, and investigated the HPAECs Micro-electronics impedance using Real Time Cellular Analysis. It was found that the down-regulation of TNF- α expression was more significant when MSC was used in combination with S1P. The combination effection mainly worked on S1PR2, S1PR3 and SphK2. The results show that when MSCs were used in combination with S1P, the selectivity of S1P receptors was increased and the homeostatic control of S1P concentration was improved through regulation of expression of S1P metabolic enzymes. The study found that, as a potential treatment, MSCs could work on multiple S1P related genes simultaneously. When it was used in combination with S1P, the expression regulation result of related genes was not simply the superposition of each other, but more significant outcome was obtained. This study establishes the experimental basis for further exploring the efficacy of improving endothelial barrier function in acute lung injury, using MSCs in combination with S1P and their possible synergistic mechanism.

  1. Disruption of retinoic acid receptor alpha reveals the growth promoter face of retinoic acid.

    Giulia Somenzi

    2007-09-01

    Full Text Available Retinoic acid (RA, the bioactive derivative of Vitamin A, by epigenetically controlling transcription through the RA-receptors (RARs, exerts a potent antiproliferative effect on human cells. However, a number of studies show that RA can also promote cell survival and growth. In the course of one of our studies we observed that disruption of RA-receptor alpha, RARalpha, abrogates the RA-mediated growth-inhibitory effects and unmasks the growth-promoting face of RA (Ren et al., Mol. Cell. Biol., 2005, 25:10591. The objective of this study was to investigate whether RA can differentially govern cell growth, in the presence and absence of RARalpha, through differential regulation of the "rheostat" comprising ceramide (CER, the sphingolipid with growth-inhibitory activity, and sphingosine-1-phosphate (S1P, the sphingolipid with prosurvival activity.We found that functional inhibition of endogenous RARalpha in breast cancer cells by using either RARalpha specific antagonists or a dominant negative RARalpha mutant hampers on one hand the RA-induced upregulation of neutral sphingomyelinase (nSMase-mediated CER synthesis, and on the other hand the RA-induced downregulation of sphingosine kinase 1, SK1, pivotal for S1P synthesis. In association with RA inability to regulate the sphingolipid rheostat, cells not only survive, but also grow more in response to RA both in vitro and in vivo. By combining genetic, pharmacological and biochemical approaches, we mechanistically demonstrated that RA-induced growth is, at least in part, due to non-RAR-mediated activation of the SK1-S1P signaling.In the presence of functional RARalpha, RA inhibits cell growth by concertedly, and inversely, modulating the CER and S1P synthetic pathways. In the absence of a functional RARalpha, RA-in a non-RAR-mediated fashion-promotes cell growth by activating the prosurvival S1P signaling. These two distinct, yet integrated processes apparently concur to the growth-promoter effects

  2. Abscisic Acid–Responsive Guard Cell Metabolomes of Arabidopsis Wild-Type and gpa1 G-Protein Mutants[C][W

    Jin, Xiaofen; Wang, Rui-Sheng; Zhu, Mengmeng; Jeon, Byeong Wook; Albert, Reka; Chen, Sixue; Assmann, Sarah M.

    2013-01-01

    Individual metabolites have been implicated in abscisic acid (ABA) signaling in guard cells, but a metabolite profile of this specialized cell type is lacking. We used liquid chromatography–multiple reaction monitoring mass spectrometry for targeted analysis of 85 signaling-related metabolites in Arabidopsis thaliana guard cell protoplasts over a time course of ABA treatment. The analysis utilized ∼350 million guard cell protoplasts from ∼30,000 plants of the Arabidopsis Columbia accession (Col) wild type and the heterotrimeric G-protein α subunit mutant, gpa1, which has ABA-hyposensitive stomata. These metabolomes revealed coordinated regulation of signaling metabolites in unrelated biochemical pathways. Metabolites clustered into different temporal modules in Col versus gpa1, with fewer metabolites showing ABA-altered profiles in gpa1. Ca2+-mobilizing agents sphingosine-1-phosphate and cyclic adenosine diphosphate ribose exhibited weaker ABA-stimulated increases in gpa1. Hormone metabolites were responsive to ABA, with generally greater responsiveness in Col than in gpa1. Most hormones also showed different ABA responses in guard cell versus mesophyll cell metabolomes. These findings suggest that ABA functions upstream to regulate other hormones, and are also consistent with G proteins modulating multiple hormonal signaling pathways. In particular, indole-3-acetic acid levels declined after ABA treatment in Col but not gpa1 guard cells. Consistent with this observation, the auxin antagonist α-(phenyl ethyl-2-one)-indole-3-acetic acid enhanced ABA-regulated stomatal movement and restored partial ABA sensitivity to gpa1. PMID:24368793

  3. Nuclear Receptors and Multiple Endocrine Neoplasia type 1 (MEN1)

    Dreijerink, K.M.A.

    2009-01-01

    Multiple Endocrine Neoplasia type 1 (MEN1) is an inherited syndrome that is characterized by the occurrence of tumours of the parathyroid glands, gastroenteropancreatic tumours, pitui-tary gland adenomas, as well as adrenal adenomas and neuro-endocrine tumours, often at a young age. MEN1 tumours can

  4. Agonist mediated fetal muscle-type nicotinic acetylcholine receptor desensitization

    The exposure of a developing embryo or fetus to teratogenic alkaloids from plants has the potential to cause developmental defects in livestock due to the inhibition of fetal movement by alkaloids. The mechanism behind the inhibition of fetal movement is the desensitization of fetal muscle-type nico...

  5. Angiotensin-II type 1 receptor gene polymorphism and diabetic microangiopathy

    Tarnow, L; Cambien, Francois; Rossing, P

    1996-01-01

    with proliferative retinopathy and without diabetic retinopathy was found either: 77 (50%) / 66 (42%) / 13 (8%) vs. 42 (63%) / 22 (33%) / 3 (4%) had AA/AC/CC genotypes, respectively. CONCLUSIONS: The A1166-->C polymorphism in the angiotensin-II type 1 receptor gene does not contribute to the genetic susceptibility...... is present particularly in vascular smooth muscle cells, myocardium and the kidney. A transversion of adenine to cytosine at nucleotide position 1166 in the gene coding for the angiotensin-II type 1 receptor has been associated with hypertension in the non-diabetic population. METHODS: We studied...... the relationship between the A1166-->C polymorphism in the angiotensin-II type 1 receptor gene in patients with insulin dependent diabetes mellitus (IDDM) and diabetic nephropathy (121 men, 77 women, age 41 +/- 10 years, diabetes duration 27 +/- 8 years) and in IDDM patients with normoalbuminuria (116 men, 74...

  6. Physiology and physiopathology of central type Benzodiazepine receptors: Study in the monkey and in human brain using positron emission tomography

    Hantraye, P.

    1987-01-01

    A new non-invasive technique that allows to study in a living subject central type benzodiazepine receptors is developed. A combined approach is applied using a specific positron-emitting radiotracer for the in vivo labelling of the receptors and positron emission tomography allowing, by external detection, a quantitative determination of tissue radioactivity. The radioligand used for the in vivo labelling of benzodiazepine receptors is the antagonist RO 15-1788 labelled with carbon 11. The various stages of the study are described: in vivo characterization in the monkey of central type benzodiazepine receptors; characterization of central type benzodiazepine receptors in human brain using selective molecules for the BZ1 benzodiazepine subclass; demonstration of the heterogeneity of central type benzodiazepine receptors in the brain; study of pathological alteration of benzodiazepine receptors in experimental epilepsy [fr

  7. Effects of angiotensin II type 1 receptor blocker on bones in mice with type 1 diabetes induced by streptozotocin.

    Zhang, Yan; Diao, Teng-Yue; Gu, Sa-Sa; Wu, Shu-Yan; Gebru, Yoseph A; Chen, Xi; Wang, Jing-Yu; Ran, Shu; Wong, Man-Sau

    2014-09-01

    This study was performed to address the pathological roles of the skeletal renin-angiotensin system (RAS) in type 1 diabetes-induced osteoporosis and the effects of the angiotensin II type 1 receptor blocker losartan on bones in diabetic mice. Bone histomorphology was detected by H&E staining, Safranin O staining and X-ray radiography. Micro-CT was performed for the analysis of bone parameters. Gene and protein expression were determined by RT-PCR and immunoblotting. Type 1 diabetic mice displayed osteopenia phenotype, and losartan treatment had no osteoprotective effects on diabetic mice as shown by the reduction of bone mineral density and microarchitectural parameters at the proximal metaphysis of the tibia. The mRNA expression of AGT, renin receptor and ACE, and protein expression of renin and AT1R were markedly up-regulated in the bones of vehicle-treated diabetic mice compared to those of non-diabetic mice. The treatment with losartan further significantly increased the expression of AGT, renin, angiotensin II and AT1R, and reduced the expression of AT2R receptor as compared to those of diabetic mice. Local bone RAS functionally played a role in the development of type 1 diabetic osteoporosis, and losartan had no bone-sparing function in diabetes mice because of enhance skeletal RAS activity. © The Author(s) 2013.

  8. [Severe type A insulin resistance syndrome due to a mutation in the insulin receptor gene].

    Ros, P; Colino-Alcol, E; Grasso, V; Barbetti, F; Argente, J

    2015-01-01

    Insulin resistance syndromes without lipodystrophy are an infrequent and heterogeneous group of disorders with variable clinical phenotypes, associated with hyperglycemia and hyperinsulinemia. The three conditions related to mutations in the insulin receptor gene are leprechaunism or Donohue syndrome, Rabson-Mendenhall syndrome, and Type A syndrome. A case is presented on a patient diagnosed with type A insulin resistance, defined by the triad of extreme insulin resistance, acanthosis nigricans, and hyperandrogenism, carrying a heterozygous mutation in exon 19 of the insulin receptor gene coding for its tyrosine kinase domain that is crucial for the catalytic activity of the receptor. The molecular basis of the syndrome is reviewed, focusing on the structure-function relationships of the insulin receptor, knowing that the criteria for survival are linked to residual insulin receptor function. It is also pointed out that, although type A insulin resistance appears to represent a somewhat less severe condition, these patients have a high morbidity and their treatment is still unsatisfactory. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  9. Nuclear receptor/microRNA circuitry links muscle fiber type to energy metabolism.

    Gan, Zhenji; Rumsey, John; Hazen, Bethany C; Lai, Ling; Leone, Teresa C; Vega, Rick B; Xie, Hui; Conley, Kevin E; Auwerx, Johan; Smith, Steven R; Olson, Eric N; Kralli, Anastasia; Kelly, Daniel P

    2013-06-01

    The mechanisms involved in the coordinate regulation of the metabolic and structural programs controlling muscle fitness and endurance are unknown. Recently, the nuclear receptor PPARβ/δ was shown to activate muscle endurance programs in transgenic mice. In contrast, muscle-specific transgenic overexpression of the related nuclear receptor, PPARα, results in reduced capacity for endurance exercise. We took advantage of the divergent actions of PPARβ/δ and PPARα to explore the downstream regulatory circuitry that orchestrates the programs linking muscle fiber type with energy metabolism. Our results indicate that, in addition to the well-established role in transcriptional control of muscle metabolic genes, PPARβ/δ and PPARα participate in programs that exert opposing actions upon the type I fiber program through a distinct muscle microRNA (miRNA) network, dependent on the actions of another nuclear receptor, estrogen-related receptor γ (ERRγ). Gain-of-function and loss-of-function strategies in mice, together with assessment of muscle biopsies from humans, demonstrated that type I muscle fiber proportion is increased via the stimulatory actions of ERRγ on the expression of miR-499 and miR-208b. This nuclear receptor/miRNA regulatory circuit shows promise for the identification of therapeutic targets aimed at maintaining muscle fitness in a variety of chronic disease states, such as obesity, skeletal myopathies, and heart failure.

  10. A chimeric antigen receptor for TRAIL-receptor 1 induces apoptosis in various types of tumor cells.

    Kobayashi, Eiji; Kishi, Hiroyuki; Ozawa, Tatsuhiko; Hamana, Hiroshi; Nakagawa, Hidetoshi; Jin, Aishun; Lin, Zhezhu; Muraguchi, Atsushi

    2014-10-31

    Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its associated receptors (TRAIL-R/TR) are attractive targets for cancer therapy because TRAIL induces apoptosis in tumor cells through TR while having little cytotoxicity on normal cells. Therefore, many agonistic monoclonal antibodies (mAbs) specific for TR have been produced, and these induce apoptosis in multiple tumor cell types. However, some TR-expressing tumor cells are resistant to TR-specific mAb-induced apoptosis. In this study, we constructed a chimeric antigen receptor (CAR) of a TRAIL-receptor 1 (TR1)-specific single chain variable fragment (scFv) antibody (TR1-scFv-CAR) and expressed it on a Jurkat T cell line, the KHYG-1 NK cell line, and human peripheral blood lymphocytes (PBLs). We found that the TR1-scFv-CAR-expressing Jurkat cells killed target cells via TR1-mediated apoptosis, whereas TR1-scFv-CAR-expressing KHYG-1 cells and PBLs killed target cells not only via TR1-mediated apoptosis but also via CAR signal-induced cytolysis, resulting in cytotoxicity on a broader range if target cells than with TR1-scFv-CAR-expressing Jurkat cells. The results suggest that TR1-scFv-CAR could be a new candidate for cancer gene therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Membrane Estrogen Receptor-α Interacts with Metabotropic Glutamate Receptor Type 1a to Mobilize Intracellular Calcium in Hypothalamic Astrocytes

    Kuo, John; Hariri, Omid R.; Bondar, Galyna; Ogi, Julie; Micevych, Paul

    2009-01-01

    Estradiol, acting on a membrane-associated estrogen receptor-α (mERα), induces an increase in free cytoplasmic calcium concentration ([Ca2+]i) needed for progesterone synthesis in hypothalamic astrocytes. To determine whether rapid estradiol signaling involves an interaction of mERα with metabotropic glutamate receptor type 1a (mGluR1a), changes in [Ca2+]i were monitored with the calcium indicator, Fluo-4 AM, in primary cultures of female postpubertal hypothalamic astrocytes. 17β-Estradiol over a range of 1 nm to 100 nm induced a maximal increase in [Ca2+]i flux measured as a change in relative fluorescence [ΔF Ca2+ = 615 ± 36 to 641 ± 47 relative fluorescent units (RFU)], whereas 0.1 nm of estradiol stimulated a moderate [Ca2+]i increase (275 ± 16 RFU). The rapid estradiol-induced [Ca2+]i flux was blocked with 1 μm of the estrogen receptor antagonist ICI 182,780 (635 ± 24 vs. 102 ± 11 RFU, P estradiol-induced membrane signaling in astrocytes. PMID:18948402

  12. The disintegrin and metalloproteinase ADAM12 contributes to TGF-beta signaling through interaction with the type II receptor

    Atfi, Azeddine; Dumont, Emmanuelle; Colland, Frédéric

    2007-01-01

    Transforming growth factor-beta (TGF-beta) regulates a wide variety of biological processes through two types of Ser/Thr transmembrane receptors: the TGF-beta type I receptor and the TGF-beta type II receptor (TbetaRII). Upon ligand binding, TGF-beta type I receptor activated by TbetaRII propagat......RII protein presumably by suppressing the association of TbetaRII with Smad7. These results define ADAM12 as a new partner of TbetaRII that facilitates its trafficking to early endosomes in which activation of the Smad pathway is initiated....

  13. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor

    Yan Zhencheng; Liu Daoyan; Zhang Lili; Shen Chenyi; Ma Qunli; Cao Tingbing; Wang Lijuan; Nie Hai; Zidek, Walter; Tepel, Martin; Zhu Zhiming

    2007-01-01

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-δ (PPAR-δ)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow or a high-fat diet without and with regular endurance exercise. Exercise in rats on high-fat diet significantly reduced visceral fat mass, blood pressure, and adipocyte size (each p < 0.05). Adipocyte hypertrophy induced by high-fat diet was accompanied by increased CB1 expression in adipose tissue, whereas exercise significantly reduced CB1 expression (each p < 0.05). CB1 receptor expression and adipocyte differentiation were directly regulated by PPAR-δ. Adipocyte hypertrophy induced by high-fat diet was accompanied by reduced PPAR-δ. Furthermore, selective silencing of PPAR-δ by RNA interference in 3T3-L1-preadipocyte cells significantly increased CB1 expression from 1.00 ± 0.06 (n = 3) to 1.91 ± 0.06 (n = 3; p < 0.01) and increased adipocyte differentiation, whereas adenovirus-mediated overexpression of PPAR-δ significantly reduced CB1 expression to 0.39 ± 0.03 (n = 3; p < 0.01) and reduced adipocyte differentiation. In the presence of the CB1 antagonist rimonabant adipocyte differentiation in stimulated 3T3 L1 preadipocyte cells was significantly reduced. The study indicates that high-fat diet-induced hypertrophy of adipocytes is associated with increased CB1 receptor expression which is directly regulated by PPAR-δ. Both CB1 and PPAR-δ are intimately involved in therapeutic interventions against a most important cardiovascular risk factor

  14. Interactions between Type III receptor tyrosine phosphatases and growth factor receptor tyrosine kinases regulate tracheal tube formation in Drosophila

    Mili Jeon

    2012-04-01

    The respiratory (tracheal system of the Drosophila melanogaster larva is an intricate branched network of air-filled tubes. Its developmental logic is similar in some ways to that of the vertebrate vascular system. We previously described a unique embryonic tracheal tubulogenesis phenotype caused by loss of both of the Type III receptor tyrosine phosphatases (RPTPs, Ptp4E and Ptp10D. In Ptp4E Ptp10D double mutants, the linear tubes in unicellular and terminal tracheal branches are converted into bubble-like cysts that incorporate apical cell surface markers. This tube geometry phenotype is modulated by changes in the activity or expression of the epidermal growth factor receptor (Egfr tyrosine kinase (TK. Ptp10D physically interacts with Egfr. Here we demonstrate that the Ptp4E Ptp10D phenotype is the consequence of the loss of negative regulation by the RPTPs of three growth factor receptor TKs: Egfr, Breathless and Pvr. Reducing the activity of any of the three kinases by tracheal expression of dominant-negative mutants suppresses cyst formation. By competing dominant-negative and constitutively active kinase mutants against each other, we show that the three RTKs have partially interchangeable activities, so that increasing the activity of one kinase can compensate for the effects of reducing the activity of another. This implies that SH2-domain downstream effectors that are required for the phenotype are likely to be able to interact with phosphotyrosine sites on all three receptor TKs. We also show that the phenotype involves increases in signaling through the MAP kinase and Rho GTPase pathways.

  15. Distortion of maternal-fetal angiotensin II type 1 receptor allele transmission in pre-eclampsia.

    Morgan, L; Crawshaw, S; Baker, P N; Brookfield, J F; Broughton Pipkin, F; Kalsheker, N

    1998-01-01

    OBJECTIVE: To investigate the fetal angiotensin II type 1 receptor genotype in pre-eclampsia. DESIGN: Case-control study. POPULATION: Forty-one maternal-fetal pairs from pre-eclamptic pregnancies and 80 maternal-fetal pairs from normotensive pregnancies. METHODS: Maternal and fetal DNA was genotyped at three diallelic polymorphisms, at nucleotides 573, 1062, and 1166, in the coding exon of the angiotensin II type 1 receptor gene, and at a dinucleotide repeat polymorphism in its 3' flanking region. RESULTS: Allele and genotype frequencies at the four polymorphic regions investigated did not differ between pre-eclamptic and normotensive groups, in either fetal or maternal samples. Mothers heterozygous for the dinucleotide repeat allele designated A4 transmitted this allele to the fetus in 15 of 18 informative pre-eclamptic pregnancies and in eight of 26 normotensive pregnancies. This was greater than the expected probability in pre-eclamptic pregnancies (p=0.04) and less than expected in normotensive pregnancies (p<0.005). The 573T variant, which is in partial linkage disequilibrium with the A4 allele, showed a similar distortion of maternal-fetal transmission. CONCLUSION: Angiotensin II type 1 receptor gene expression in the fetus may contribute to the aetiology of pre-eclampsia. It is unclear whether susceptibility is conferred by the fetal genotype acting alone, or by allele sharing by mother and fetus. Possible mechanisms for the effect of the angiotensin II type 1 receptor gene are suggested by the association of the 573T variant with low levels of surface receptor expression on platelets. If receptor expression is similarly genetically determined in the placenta, responsiveness to angiotensin II may be affected, with the potential to influence placentation or placental prostaglandin secretion. PMID:9719367

  16. Three mutations switch H7N9 influenza to human-type receptor specificity

    de Vries, Robert P.; Peng, Wenjie; Grant, Oliver C.; Thompson, Andrew J.; Zhu, Xueyong; Bouwman, Kim M.; de la Pena, Alba T. Torrents; van Breemen, Marielle J.; Ambepitiya Wickramasinghe, Iresha N.; de Haan, Cornelis A. M.; Yu, Wenli; McBride, Ryan; Sanders, Rogier W.; Woods, Robert J.; Verheije, Monique H.; Wilson, Ian A.; Paulson, James C.; Fernandez-Sesma, Ana

    2017-06-15

    The avian H7N9 influenza outbreak in 2013 resulted from an unprecedented incidence of influenza transmission to humans from infected poultry. The majority of human H7N9 isolates contained a hemagglutinin (HA) mutation (Q226L) that has previously been associated with a switch in receptor specificity from avian-type (NeuAcα2-3Gal) to human-type (NeuAcα2-6Gal), as documented for the avian progenitors of the 1957 (H2N2) and 1968 (H3N2) human influenza pandemic viruses. While this raised concern that the H7N9 virus was adapting to humans, the mutation was not sufficient to switch the receptor specificity of H7N9, and has not resulted in sustained transmission in humans. To determine if the H7 HA was capable of acquiring human-type receptor specificity, we conducted mutation analyses. Remarkably, three amino acid mutations conferred a switch in specificity for human-type receptors that resembled the specificity of the 2009 human H1 pandemic virus, and promoted binding to human trachea epithelial cells.

  17. Erratum Aldosterone synthase C-344T, angiotensin II type 1 receptor ...

    Aldosterone synthase C-344T, angiotensin II type 1 receptor A1166C and 11-β hydroxysteroid dehydrogenase G534A gene polymorphisms and essential hypertension in the population of Odisha, India. Manisha Patnaik, Pallabi Pati, Surendra N. Swain, Manoj K. Mohapatra, Bhagirathi Dwibedi, Shantanu K. Kar.

  18. Centrally Mediated Cardiovascular Actions of the Angiotensin II Type 2 Receptor

    Steckelings, U Muscha; Kloet, Annette de; Sumners, Colin

    2017-01-01

    Sustained increases in the activity of the sympathetic neural pathways that exit the brain and which increase blood pressure (BP) are a major underlying factor in resistant hypertension. Recently available information on the occurrence of angiotensin II type 2 receptors (AT2Rs) within or adjacent...

  19. Localization and functional roles of corticotropin-releasing factor receptor type 2 in the cerebellum

    Gounko, Natalia V.; Gramsbergen, Albert; van der Want, Johannes J. L.

    The corticotropin-releasing factor (CRF) type 2 receptor has three splice variants alpha, beta, and gamma. In the rodent brain only CRF-R2 alpha is present. In the cerebellum, CRF-R2 alpha has two different isoforms: a full-length form (fl) and truncated (tr). Both forms CRF-R2 have a unique

  20. The angiotensin type 2 receptor agonist Compound 21 elicits cerebroprotection in endothelin-1 induced ischemic stroke

    Joseph, Jason P; Mecca, Adam P; Regenhardt, Robert W

    2014-01-01

    Evidence indicates that angiotensin II type 2 receptors (AT2R) exert cerebroprotective actions during stroke. A selective non-peptide AT2R agonist, Compound 21 (C21), has been shown to exert beneficial effects in models of cardiac and renal disease, as well as hemorrhagic stroke. Here, we hypothe...

  1. Three mutations switch H7N9 influenza to human-type receptor specificity.

    Robert P de Vries

    2017-06-01

    Full Text Available The avian H7N9 influenza outbreak in 2013 resulted from an unprecedented incidence of influenza transmission to humans from infected poultry. The majority of human H7N9 isolates contained a hemagglutinin (HA mutation (Q226L that has previously been associated with a switch in receptor specificity from avian-type (NeuAcα2-3Gal to human-type (NeuAcα2-6Gal, as documented for the avian progenitors of the 1957 (H2N2 and 1968 (H3N2 human influenza pandemic viruses. While this raised concern that the H7N9 virus was adapting to humans, the mutation was not sufficient to switch the receptor specificity of H7N9, and has not resulted in sustained transmission in humans. To determine if the H7 HA was capable of acquiring human-type receptor specificity, we conducted mutation analyses. Remarkably, three amino acid mutations conferred a switch in specificity for human-type receptors that resembled the specificity of the 2009 human H1 pandemic virus, and promoted binding to human trachea epithelial cells.

  2. Soluble urokinase-type plasminogen activator receptor forms in plasma as markers of atherosclerotic plaque vulnerability

    Olson, Fredrik J; Thurison, Tine; Ryndel, Mikael

    2009-01-01

    OBJECTIVES:: To test if circulating forms of the soluble urokinase-type plasminogen activator receptor (suPAR) are potential biomarkers of plaque vulnerability. DESIGN AND METHODS:: Plasma concentrations of suPAR(I-III), suPAR(II-III) and uPAR(I) were measured by time-resolved fluorescence immuno...

  3. Cortical Serotonin Type-2 Receptor Density in Parents of Children with Autism Spectrum Disorders

    Goldberg, Jeremy; Anderson, George M.; Zwaigenbaum, Lonnie; Hall, Geoffrey B. C.; Nahmias, Claude; Thompson, Ann; Szatmari, Peter

    2009-01-01

    Parents (N = 19) of children with autism spectrum disorders (ASD) and adult controls (N = 17) underwent positron emission tomography (PET) using [[superscript 18]F]setoperone to image cortical serotonin type-2 (5-HT2) receptors. The 5-HT2 binding potentials (BPs) were calculated by ratioing [[superscript 18]F]setoperone intensity in regions of…

  4. Increased transient receptor potential canonical type 3 channels in vasculature from hypertensive rats

    Liu, Daoyan; Yang, Dachun; He, Hongbo

    2009-01-01

    We tested the hypothesis that transient receptor potential canonical type 3 (TRPC3) channels are increased in vascular smooth muscle cells and aortic tissue from spontaneously hypertensive rats (SHR) compared with normotensive Wistar Kyoto rats. Expression of TRPC3 was analyzed by immunohistochem...

  5. Transient receptor potential canonical type 3 channels and blood pressure in humans

    Thilo, Florian; Baumunk, Daniel; Krause, Hans

    2009-01-01

    There is evidence that transient receptor potential canonical type 3 (TRPC3) cation channels are involved in the regulation of blood pressure, but this has not been studied using human renal tissue. We tested the hypothesis that the expression of TRPC3 in human renal tissue is associated with blood...

  6. [Functional properties of taste bud cells. Mechanisms of afferent neurotransmission in Type II taste receptor cells].

    Romanov, R A

    2013-01-01

    Taste Bud cells are heterogeneous in their morphology and functionality. These cells are responsible for sensing a wide variety of substances and for associating detected compounds with a different taste: bitter, sweet, salty, sour and umami. Today we know that each of the five basic tastes corresponds to distinct cell populations organized into three basic morpho-functional cell types. In addition, some receptor cells of the taste bud demonstrate glia-related functions. In this article we expand on some properties of these three morphological receptor cell types. Main focus is devoted to the Type II cells and unusual mechanism for afferent neurotransmission in these cells. Taste cells of the Type II consist of three populations detecting bitter, sweet and umami tastes, and, thus, evoke a serious scientific interest.

  7. Collagen Type I as a Ligand for Receptor-Mediated Signaling

    Iris Boraschi-Diaz

    2017-05-01

    Full Text Available Collagens form the fibrous component of the extracellular matrix in all multi-cellular animals. Collagen type I is the most abundant collagen present in skin, tendons, vasculature, as well as the organic portion of the calcified tissue of bone and teeth. This review focuses on numerous receptors for which collagen acts as a ligand, including integrins, discoidin domain receptors DDR1 and 2, OSCAR, GPVI, G6b-B, and LAIR-1 of the leukocyte receptor complex (LRC and mannose family receptor uPARAP/Endo180. We explore the process of collagen production and self-assembly, as well as its degradation by collagenases and gelatinases in order to predict potential temporal and spatial sites of action of different collagen receptors. While the interactions of the mature collagen matrix with integrins and DDR are well-appreciated, potential signals from immature matrix as well as collagen degradation products are possible but not yet described. The role of multiple collagen receptors in physiological processes and their contribution to pathophysiology of diseases affecting collagen homeostasis require further studies.

  8. Modulation of type II TGF-β receptor degradation by integrin-linked kinase.

    Vi, Linda; Boo, Stellar; Sayedyahossein, Samar; Singh, Randeep K; McLean, Sarah; Di Guglielmo, Gianni M; Dagnino, Lina

    2015-03-01

    Cutaneous responses to injury, infection, and tumor formation involve the activation of resident dermal fibroblasts and subsequent transition to myofibroblasts. The key for induction of myofibroblast differentiation is the activation of transforming growth factor-β (TGF-β) receptors and stimulation of integrins and their associated proteins, including integrin-linked kinase (ILK). Cross-talk processes between TGF-β and ILK are crucial for myofibroblast formation, as ILK-deficient dermal fibroblasts exhibit impaired responses to TGF-β receptor stimulation. We now show that ILK associates with type II TGF-β receptors (TβRII) in ligand- and receptor kinase activity-independent manners. In cells with targeted Ilk gene inactivation, cellular levels of TβRII are decreased, through mechanisms that involve enhanced ubiquitination and proteasomal degradation. Partitioning of TGF-β receptors into membrane has been linked to proteasome-dependent receptor degradation. We found that interfering with membrane raft formation in ILK-deficient cells restored TβRII levels and signaling. These observations support a model whereby ILK functions in fibroblasts to direct TβRII away from degradative pathways during their differentiation into myofibroblasts.

  9. Type 1 diabetes promotes disruption of advanced atherosclerotic lesions in LDL receptor-deficient mice

    Johansson, Fredrik; Kramer, Farah; Barnhart, Shelley; Kanter, Jenny E.; Vaisar, Tomas; Merrill, Rachel D.; Geng, Linda; Oka, Kazuhiro; Chan, Lawrence; Chait, Alan; Heinecke, Jay W.; Bornfeldt, Karin E.

    2008-01-01

    Cardiovascular disease, largely because of disruption of atherosclerotic lesions, accounts for the majority of deaths in people with type 1 diabetes. Recent mouse models have provided insights into the accelerated atherosclerotic lesion initiation in diabetes, but it is unknown whether diabetes directly worsens more clinically relevant advanced lesions. We therefore used an LDL receptor-deficient mouse model, in which type 1 diabetes can be induced at will, to investigate the effects of diabe...

  10. The mechanisms behind decreased internalization of angiotensin II type 1 receptor.

    Bian, Jingwei; Zhang, Suli; Yi, Ming; Yue, Mingming; Liu, Huirong

    2018-04-01

    The internalization of angiotensin II type 1 receptor (AT 1 R) plays an important role in maintaining cardiovascular homeostasis. Decreased receptor internalization is closely related to cardiovascular diseases induced by the abnormal activation of AT 1 R, such as hypertension. However, the mechanism behind reduced AT 1 R internalization is not fully understood. This review focuses on four parts of the receptor internalization process (the combination of agonists and receptors, receptor phosphorylation, endocytosis, and recycling) and summarizes the possible mechanisms by which AT 1 R internalization is reduced based on these four parts of the process. (1) The agonist has a large molecular weight or a stronger ability to hydrolyze phosphatidylinositol 4,5-bisphosphate (PtdIns (4,5) P 2 ), which can increase the consumption of PtdIns (4,5) P 2 . (2) AT 1 R phosphorylation is weakened because of an abnormal function of phosphorylated kinase or changes in phospho-barcoding and GPCR-β-arrestin complex conformation. (3) The abnormal formation of vesicles or AT 1 R heterodimers with fewer endocytic receptors results in less AT 1 R endocytosis. (4) The enhanced activity and upregulated expression of small GTP-binding protein 4 (Rab4) and 11 (Rab11), which regulate receptor recycling, and phosphatidylinositol 3-kinase increase AT 1 R recycling. In addition, lower expression of AT 1 R-associated protein (ATRAP) or higher expression of AT 1 R-associated protein 1 (ARAP1) can reduce receptor internalization. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Endogenous ligands for C-type lectin receptors: the true regulators of immune homeostasis.

    García-Vallejo, Juan J; van Kooyk, Yvette

    2009-07-01

    C-type lectin receptors (CLRs) have long been known as pattern-recognition receptors implicated in the recognition of pathogens by the innate immune system. However, evidence is accumulating that many CLRs are also able to recognize endogenous 'self' ligands and that this recognition event often plays an important role in immune homeostasis. In the present review, we focus on the human and mouse CLRs for which endogenous ligands have been described. Special attention is given to the signaling events initiated upon recognition of the self ligand and the regulation of glycosylation as a switch modulating CLR recognition, and therefore, immune homeostasis.

  12. Adiponectin, Leptin, and Leptin Receptor in Obese Patients with Type 2 Diabetes Treated with Insulin Detemir

    Paweł Olczyk

    2017-07-01

    Full Text Available The aim of the present study is to quantitatively assess the expression of selected regulatory molecules, such as leptin, leptin receptor, and adiponectin in the blood of obese patients with type 2 diabetes both before treatment and after six months of pharmacological therapy with the long-lasting insulin analogue, insulin detemir. A significant decrease in the analysed regulatory molecules, i.e., leptin receptor and adiponectin, was found in blood plasma of the patients with untreated type 2 diabetes. These changes were accompanied by an increase in plasma leptin concentrations. Insulin treatment resulted in the normalization of plasma leptin receptor and adiponectin concentrations. The circulating leptin level did not change following anti-diabetic therapy with insulin detemir. Gender was a significant factor modifying the circulating level of all the analysed regulatory active compounds. Bioinformatic analysis was performed using Matlab with the Signal Processing Toolbox. The conducted discriminant analysis revealed that the leptin receptor, Δw(19, and adiponectin, Δw(21, were the parameters undergoing the most significant quantitative changes during the six-month therapy with insulin detemir. The conducted examinations indicated the contribution of adipocytokines—the biologically-active mediators of systemic metabolism, such as leptin and adiponectin in the pathomechanism of disorders being the basis for obesity which leads to development of insulin resistance, which, in turn, results in the occurrence of type 2 diabetes.

  13. C-type lectins do not act as functional receptors for filovirus entry into cells

    Matsuno, Keita; Nakayama, Eri; Noyori, Osamu [Department of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo (Japan); Marzi, Andrea; Ebihara, Hideki [Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT (United States); Irimura, Tatsuro [Graduate School of Pharmaceutical Science, University of Tokyo, Tokyo (Japan); Feldmann, Heinz [Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT (United States); Takada, Ayato, E-mail: atakada@czc.hokudai.ac.jp [Department of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo (Japan)

    2010-12-03

    Research highlights: {yields} Filovirus glycoprotein (GP) having a deficient receptor binding region were generated. {yields} Mutant GPs mediated virus entry less efficiently than wild-type GP. {yields} Mutant GPs bound to C-type lectins but not mediated entire steps of cellular entry. {yields} C-type lectins do not independently mediate filovirus entry into cells. {yields} Other molecule(s) are required for C-type lectin-mediated entry of filoviruses. -- Abstract: Cellular C-type lectins have been reported to facilitate filovirus infection by binding to glycans on filovirus glycoprotein (GP). However, it is not clearly known whether interaction between C-type lectins and GP mediates all the steps of virus entry (i.e., attachment, internalization, and membrane fusion). In this study, we generated vesicular stomatitis viruses pseudotyped with mutant GPs that have impaired structures of the putative receptor binding regions and thus reduced ability to infect the monkey kidney cells that are routinely used for virus propagation. We found that infectivities of viruses with the mutant GPs dropped in C-type lectin-expressing cells, parallel with those in the monkey kidney cells, whereas binding activities of these GPs to the C-type lectins were not correlated with the reduced infectivities. These results suggest that C-type lectin-mediated entry of filoviruses requires other cellular molecule(s) that may be involved in virion internalization or membrane fusion.

  14. C-type lectins do not act as functional receptors for filovirus entry into cells

    Matsuno, Keita; Nakayama, Eri; Noyori, Osamu; Marzi, Andrea; Ebihara, Hideki; Irimura, Tatsuro; Feldmann, Heinz; Takada, Ayato

    2010-01-01

    Research highlights: → Filovirus glycoprotein (GP) having a deficient receptor binding region were generated. → Mutant GPs mediated virus entry less efficiently than wild-type GP. → Mutant GPs bound to C-type lectins but not mediated entire steps of cellular entry. → C-type lectins do not independently mediate filovirus entry into cells. → Other molecule(s) are required for C-type lectin-mediated entry of filoviruses. -- Abstract: Cellular C-type lectins have been reported to facilitate filovirus infection by binding to glycans on filovirus glycoprotein (GP). However, it is not clearly known whether interaction between C-type lectins and GP mediates all the steps of virus entry (i.e., attachment, internalization, and membrane fusion). In this study, we generated vesicular stomatitis viruses pseudotyped with mutant GPs that have impaired structures of the putative receptor binding regions and thus reduced ability to infect the monkey kidney cells that are routinely used for virus propagation. We found that infectivities of viruses with the mutant GPs dropped in C-type lectin-expressing cells, parallel with those in the monkey kidney cells, whereas binding activities of these GPs to the C-type lectins were not correlated with the reduced infectivities. These results suggest that C-type lectin-mediated entry of filoviruses requires other cellular molecule(s) that may be involved in virion internalization or membrane fusion.

  15. γ-Aminobutyric Acid Type B (GABAB) Receptor Internalization Is Regulated by the R2 Subunit*

    Hannan, Saad; Wilkins, Megan E.; Dehghani-Tafti, Ebrahim; Thomas, Philip; Baddeley, Stuart M.; Smart, Trevor G.

    2011-01-01

    γ-Aminobutyric acid type B (GABAB) receptors are important for slow synaptic inhibition in the CNS. The efficacy of inhibition is directly related to the stability of cell surface receptors. For GABAB receptors, heterodimerization between R1 and R2 subunits is critical for cell surface expression and signaling, but how this determines the rate and extent of receptor internalization is unknown. Here, we insert a high affinity α-bungarotoxin binding site into the N terminus of the R2 subunit and reveal its dominant role in regulating the internalization of GABAB receptors in live cells. To simultaneously study R1a and R2 trafficking, a new α-bungarotoxin binding site-labeling technique was used, allowing α-bungarotoxin conjugated to different fluorophores to selectively label R1a and R2 subunits. This approach demonstrated that R1a and R2 are internalized as dimers. In heterologous expression systems and neurons, the rates and extents of internalization for R1aR2 heteromers and R2 homomers are similar, suggesting a regulatory role for R2 in determining cell surface receptor stability. The fast internalization rate of R1a, which has been engineered to exit the endoplasmic reticulum, was slowed to that of R2 by truncating the R1a C-terminal tail or by removing a dileucine motif in its coiled-coil domain. Slowing the rate of internalization by co-assembly with R2 represents a novel role for GPCR heterodimerization whereby R2 subunits, via their C terminus coiled-coil domain, mask a dileucine motif on R1a subunits to determine the surface stability of the GABAB receptor. PMID:21724853

  16. Neomycin is a platelet-derived growth factor (PDGF) antagonist that allows discrimination of PDGF alpha- and beta-receptor signals in cells expressing both receptor types.

    Vassbotn, F S; Ostman, A; Siegbahn, A; Holmsen, H; Heldin, C H

    1992-08-05

    The aminoglycoside neomycin has recently been found to affect certain platelet-derived growth factor (PDGF) responses in C3H/10T1/2 C18 fibroblasts. Using porcine aortic endothelial cells transfected with PDGF alpha- or beta-receptors, we explored the possibility that neomycin interferes with the interaction between the different PDGF isoforms and their receptors. We found that neomycin (5 mM) inhibited the binding of 125I-PDGF-BB to the alpha-receptor with only partial effect on the binding of 125I-PDGF-AA; in contrast, the binding of 125I-PDGF-BB to the beta-receptor was not affected by the aminoglycoside. Scatchard analyses showed that neomycin (5 mM) decreased the number of binding sites for PDGF-BB on alpha-receptor-expressing cells by 87%. Together with cross-competition studies with 125I-labeled PDGF homodimers, the effect of neomycin indicates that PDGF-AA and PDGF-BB bind to both common and unique structures on the PDGF alpha-receptor. Neomycin specifically inhibited the autophosphorylation of the alpha-receptor by PDGF-BB, with less effect on the phosphorylation induced by PDGF-AA and no effect on the phosphorylation of the beta-receptor by PDGF-BB. Thus, neomycin is a PDGF isoform- and receptor-specific antagonist that provides a possibility to compare the signal transduction pathways of alpha- and beta-receptors in cells expressing both receptor types. This approach was used to show that activation of PDGF beta-receptors by PDGF-BB mediated a chemotactic response in human fibroblasts, whereas activation of alpha-receptors by the same ligand inhibited chemotaxis.

  17. Mood stabilizer treatment increases serotonin type 1A receptor binding in bipolar depression

    Nugent, Allison C; Carlson, Paul J; Bain, Earle E; Eckelman, William; Herscovitch, Peter; Manji, Husseini; Zarate, Carlos A; Drevets, Wayne C

    2013-01-01

    Abnormal serotonin type 1A (5-HT1A) receptor function and binding have been implicated in the pathophysiology of mood disorders. Preclinical studies have consistently shown that stress decreases the gene expression of 5-HT1A receptors in experimental animals, and that the associated increase in hormone secretion plays a crucial role in mediating this effect. Chronic administration of the mood stabilizers lithium and divalproex (valproate semisodium) reduces glucocorticoid signaling and function in the hippocampus. Lithium has further been shown to enhance 5-HT1A receptor function. To assess whether these effects translate to human subject with bipolar disorder (BD), positron emission tomography (PET) and [18F]trans-4-fluoro-N-(2-[4-(2-methoxyphenyl) piperazino]-ethyl)-N-(2-pyridyl) cyclohexanecarboxamide ([18F]FCWAY) were used to acquire PET images of 5-HT1A receptor binding in 10 subjects with BD, before and after treatment with lithium or divalproex. Mean 5-HT1A binding potential (BPP) significantly increased following mood stabilizer treatment, most prominently in the mesiotemporal cortex (hippocampus plus amygdala). When mood state was also controlled for, treatment was associated with increases in BPP in widespread cortical areas. These preliminary findings are consistent with the hypothesis that these mood stabilizers enhance 5-HT1A receptor expression in BD, which may underscore an important component of these agents' mechanism of action. PMID:23926239

  18. Characterization of an Invertebrate-Type Dopamine Receptor of the American Cockroach, Periplaneta americana

    Britta Troppmann

    2014-01-01

    Full Text Available We have isolated a cDNA coding for a putative invertebrate-type dopamine receptor (Peadop2 from P. americana brain by using a PCR-based strategy. The mRNA is present in samples from brain and salivary glands. We analyzed the distribution of the PeaDOP2 receptor protein with specific affinity-purified polyclonal antibodies. On Western blots, PeaDOP2 was detected in protein samples from brain, subesophageal ganglion, thoracic ganglia, and salivary glands. In immunocytochemical experiments, we detected PeaDOP2 in neurons with their somata being located at the anterior edge of the medulla bilaterally innervating the optic lobes and projecting to the ventro-lateral protocerebrum. In order to determine the functional and pharmacological properties of the cloned receptor, we generated a cell line constitutively expressing PeaDOP2. Activation of PeaDOP2-expressing cells with dopamine induced an increase in intracellular cAMP. In contrast, a C-terminally truncated splice variant of this receptor did not exhibit any functional property by itself. The molecular and pharmacological characterization of the first dopamine receptor from P. americana provides the basis for forthcoming studies focusing on the significance of the dopaminergic system in cockroach behavior and physiology.

  19. Characterization of an invertebrate-type dopamine receptor of the American cockroach, Periplaneta americana.

    Troppmann, Britta; Balfanz, Sabine; Krach, Christian; Baumann, Arnd; Blenau, Wolfgang

    2014-01-06

    We have isolated a cDNA coding for a putative invertebrate-type dopamine receptor (Peadop2) from P. americana brain by using a PCR-based strategy. The mRNA is present in samples from brain and salivary glands. We analyzed the distribution of the PeaDOP2 receptor protein with specific affinity-purified polyclonal antibodies. On Western blots, PeaDOP2 was detected in protein samples from brain, subesophageal ganglion, thoracic ganglia, and salivary glands. In immunocytochemical experiments, we detected PeaDOP2 in neurons with their somata being located at the anterior edge of the medulla bilaterally innervating the optic lobes and projecting to the ventro-lateral protocerebrum. In order to determine the functional and pharmacological properties of the cloned receptor, we generated a cell line constitutively expressing PeaDOP2. Activation of PeaDOP2-expressing cells with dopamine induced an increase in intracellular cAMP. In contrast, a C-terminally truncated splice variant of this receptor did not exhibit any functional property by itself. The molecular and pharmacological characterization of the first dopamine receptor from P. americana provides the basis for forthcoming studies focusing on the significance of the dopaminergic system in cockroach behavior and physiology.

  20. Increased transient receptor potential vanilloid type 1 (TRPV1) channel expression in hypertrophic heart

    Thilo, Florian; Liu, Ying; Schulz, Nico

    2010-01-01

    The aim of this study was to compare the expression of transient receptor potential vanilloid type 1 (TRPV1) channels in hypertrophic hearts from transgenic mice showing overexpression of the catalytic subunit alpha of protein phosphatase 2A alpha (PP2Ac alpha) with wild-type mice and with TRPV1-...... alpha transgenic mice compared to wild-type mice and TRPV1-/- mice (8.6±1.3mg/g; 5.4±0.3mg/g; and 5.4±0.4mg/g; respectively; p...

  1. The TAM family receptor tyrosine kinase TYRO3 is a negative regulator of type 2 immunity

    Chan, Pamela Y.; Carrera Silva, Eugenio A.; De Kouchkovsky, Dimitri; Joannas, Leonel D.; Hao, Liming; Hu, Donglei; Huntsman, Scott; Eng, Celeste; Licona-Limón, Paula; Weinstein, Jason S.; Herbert, De’Broski R.; Craft, Joseph E.; Flavell, Richard A.; Repetto, Silvia; Correale, Jorge; Burchard, Esteban G.; Torgerson, Dara G.; Ghosh, Sourav; Rothlin, Carla V.

    2016-01-01

    Host responses against metazoan parasites or an array of environmental substances elicit type 2 immunity. Despite its protective function, type 2 immunity also drives allergic diseases. The mechanisms that regulate the magnitude of the type 2 response remain largely unknown. Here, we show that genetic ablation of a receptor tyrosine kinase encoded by Tyro3 in mice or the functional neutralization of its ortholog in human dendritic cells resulted in enhanced type 2 immunity. Furthermore, the TYRO3 agonist PROS1 was induced in T cells by the quintessential type 2 cytokine, interleukin-4. T cell–specific Pros1 knockouts phenocopied the loss of Tyro3. Thus, a PROS1-mediated feedback from adaptive immunity engages a rheostat, TYRO3, on innate immune cells to limit the intensity of type 2 responses. PMID:27034374

  2. Two types of muscarinic acetylcholine receptors in Drosophila and other arthropods.

    Collin, Caitlin; Hauser, Frank; Gonzalez de Valdivia, Ernesto; de Valdivia, Ernesto Gonzalez; Li, Shizhong; Reisenberger, Julia; Carlsen, Eva M M; Khan, Zaid; Hansen, Niels O; Puhm, Florian; Søndergaard, Leif; Niemiec, Justyna; Heninger, Magdalena; Ren, Guilin R; Grimmelikhuijzen, Cornelis J P

    2013-09-01

    Muscarinic acetylcholine receptors (mAChRs) play a central role in the mammalian nervous system. These receptors are G protein-coupled receptors (GPCRs), which are activated by the agonists acetylcholine and muscarine, and blocked by a variety of antagonists. Mammals have five mAChRs (m1-m5). In this study, we cloned two structurally related GPCRs from the fruit fly Drosophila melanogaster, which, after expression in Chinese hamster ovary cells, proved to be muscarinic acetylcholine receptors. One mAChR (the A-type; encoded by gene CG4356) is activated by acetylcholine (EC50, 5 × 10(-8) M) and muscarine (EC50, 6 × 10(-8) M) and blocked by the classical mAChR antagonists atropine, scopolamine, and 3-quinuclidinyl-benzilate (QNB), while the other (the B-type; encoded by gene CG7918) is also activated by acetylcholine, but has a 1,000-fold lower sensitivity to muscarine, and is not blocked by the antagonists. A- and B-type mAChRs were also cloned and functionally characterized from the red flour beetle Tribolium castaneum. Recently, Haga et al. (Nature 2012, 482: 547-551) published the crystal structure of the human m2 mAChR, revealing 14 amino acid residues forming the binding pocket for QNB. These residues are identical between the human m2 and the D. melanogaster and T. castaneum A-type mAChRs, while many of them are different between the human m2 and the B-type receptors. Using bioinformatics, one orthologue of the A-type and one of the B-type mAChRs could also be found in all other arthropods with a sequenced genome. Protostomes, such as arthropods, and deuterostomes, such as mammals and other vertebrates, belong to two evolutionarily distinct lineages of animal evolution that split about 700 million years ago. We found that animals that originated before this split, such as cnidarians (Hydra), had two A-type mAChRs. From these data we propose a model for the evolution of mAChRs.

  3. Two types of muscarinic acetylcholine receptors in Drosophila and other arthropods

    Collin, Caitlin Alexis; Hauser, Frank; Gonzalez de Valdivia, Ernesto I

    2013-01-01

    Muscarinic acetylcholine receptors (mAChRs) play a central role in the mammalian nervous system. These receptors are G protein-coupled receptors (GPCRs), which are activated by the agonists acetylcholine and muscarine, and blocked by a variety of antagonists. Mammals have five mAChRs (m1-m5......). In this study, we cloned two structurally related GPCRs from the fruit fly Drosophila melanogaster, which, after expression in Chinese hamster ovary cells, proved to be muscarinic acetylcholine receptors. One mAChR (the A-type; encoded by gene CG4356) is activated by acetylcholine (EC50, 5 × 10(-8) M......) and muscarine (EC50, 6 × 10(-8) M) and blocked by the classical mAChR antagonists atropine, scopolamine, and 3-quinuclidinyl-benzilate (QNB), while the other (the B-type; encoded by gene CG7918) is also activated by acetylcholine, but has a 1,000-fold lower sensitivity to muscarine, and is not blocked...

  4. Treatment of type 2 diabetes with glucagon-like peptide-1 receptor agonists

    Hansen, K B; Knop, F K; Holst, Jens Juul

    2009-01-01

    of hypoglycaemia with GLP-1 receptor agonists is low, the compounds have clinically relevant effects on body weight, and data are suggesting beneficial effects on cardiovascular risk factors. Exenatide was released in 2005 for the treatment of type 2 diabetes and liraglutide is expected to be approved by the Food......The incretin system is an area of great interest for the development of new therapies for the management of type 2 diabetes. Existing antidiabetic drugs are often insufficient at getting patients to glycaemic goals. Furthermore, current treatment modalities are not able to prevent the continued...... ongoing decline in pancreatic beta-cell function and, lastly, they have a number of side effects including hypoglycaemia and weight gain. Glucagon-like peptide-1 (GLP-1) receptor agonists are a new class of pharmacological agents, which improve glucose homeostasis in a multifaceted way. Their effects...

  5. Do cysteine residues regulate transient receptor potential canonical type 6 (TRPC6) channel protein expression?

    Thilo, Florian; Liu, Ying; Krueger, Katharina

    2012-01-01

    The regulation of calcium influx through transient receptor potential canonical type 6 channel is mandatory for the activity of human monocytes. We submit the first evidence that cysteine residues of homocysteine or acetylcysteine affect TRPC6 expression in human monocytes. We observed that patie......The regulation of calcium influx through transient receptor potential canonical type 6 channel is mandatory for the activity of human monocytes. We submit the first evidence that cysteine residues of homocysteine or acetylcysteine affect TRPC6 expression in human monocytes. We observed...... that patients with chronic renal failure had significantly elevated homocysteine levels and TRPC6 mRNA expression levels in monocytes compared to control subjects. We further observed that administration of homocysteine or acetylcysteine significantly increased TRPC6 channel protein expression compared...... to control conditions. We therefore hypothesize that cysteine residues increase TRPC6 channel protein expression in humans....

  6. Expression of Angiotensin II Types 1 and 2 Receptors in Endometriotic Lesions.

    Nakao, Takehiro; Chishima, Fumihisa; Sugitani, Masahiko; Tsujimura, Ryusuke; Hayashi, Chuyu; Yamamoto, Tatsuo

    2017-01-01

    The aim of this study was to evaluate the gene and protein expression of angiotensin type (AT) 1, AT2 receptors in endometriotic lesions and its relation to prostaglandin (PG) synthases. Endometriosis samples were obtained from 32 patients with endometriotic cysts. Endometrial tissues were obtained during operations for benign gynecological conditions. The expression of the AT1 and AT2 receptor mRNA and that of PG-endoperoxide synthase 2 and microsomal PGE2 synthase-1 (mPGES-1) was examined by quantitative RT-PCR. Immunohistochemical staining was performed for these receptors. AT1 and AT2 receptor proteins were mostly located in endometrial glandular epithelium and some stromal cells. Immunoreactivity of the receptor proteins was observed in both the eutopic endometrium and endometriotic lesions. The AT1/AT2 ratio in endometriotic cysts (median 7.29, range 1.88-187.60) was significantly increased compared with that in the eutopic endometrium in the proliferative-phase in controls (median 1.01, range 0.37-2.09, p < 0.001). There was a relationship between the AT1 mRNA expression and that of mPGES-1 mRNA in the endometriotic cysts (r = 0.394089, p < 0.05). There was a significant relationship between the mRNA expression of the AT2 receptor and that of mPGES-1 in eutopic endometrium of non-endometriotic control (r = 0.610714, p < 0.05). Renin-angiotensin system may play an important role in the pathophysiology of endometriosis. © 2016 S. Karger AG, Basel.

  7. Accessibility of receptor-bound urokinase to type-1 plasminogen activator inhibitor

    Cubellis, M.V.; Andreasen, P.; Ragno, P.; Mayer, M.; Dano, K.; Blasi, F. (Univ. of Copenhagen (Denmark))

    1989-07-01

    Urokinase plasminogen activator (uPA) interacts with a surface receptor and with specific inhibitors, such as plasminogen activator inhibitor type 1 (PAI-1). These interactions are mediated by two functionally independent domains of the molecule: the catalytic domain (at the carboxyl terminus) and the growth factor domain (at the amino terminus). The authors have now investigated whether PAI-1 can bind and inhibit receptor-bound uPA. Binding of {sup 125}I-labeled ATF (amino-terminal fragment of uPA) to human U937 monocyte-like cells can be competed for by uPA-PAI-1 complexes, but not by PAI-1 alone. Preformed {sup 125}I-labeled uPA-PAI-1 complexes can bind to uPA receptor with the same binding specificity as uPA. PAI-1 also binds to, and inhibits the activity of, receptor-bound uPA in U937 cells, as shown in U937 cells by a caseinolytic plaque assay. Plasminogen activator activity of these cells is dependent on exogenous uPA, is competed for by receptor-binding diisopropyl fluorophosphate-treated uPA, and is inhibited by the addition of PAI-1. In conclusion, in U937 cells the binding to the receptor does not shield uPA from the action of PAI-1. The possibility that in adherent cells a different localization of PAI-1 and uPA leads to protection of uPA from PAI-1 is to be considered.

  8. Role of type I interferon receptor signaling on NK cell development and functions.

    Jean Guan

    Full Text Available Type I interferons (IFN are unique cytokines transcribed from intronless genes. They have been extensively studied because of their anti-viral functions. The anti-viral effects of type I IFN are mediated in part by natural killer (NK cells. However, the exact contribution of type I IFN on NK cell development, maturation and activation has been somewhat difficult to assess. In this study, we used a variety of approaches to define the consequences of the lack of type I interferon receptor (IFNAR signaling on NK cells. Using IFNAR deficient mice, we found that type I IFN affect NK cell development at the pre-pro NK stage. We also found that systemic absence of IFNAR signaling impacts NK cell maturation with a significant increase in the CD27+CD11b+ double positive (DP compartment in all organs. However, there is tissue specificity, and only in liver and bone marrow is the maturation defect strictly dependent on cell intrinsic IFNAR signaling. Finally, using adoptive transfer and mixed bone marrow approaches, we also show that cell intrinsic IFNAR signaling is not required for NK cell IFN-γ production in the context of MCMV infection. Taken together, our studies provide novel insights on how type I IFN receptor signaling regulates NK cell development and functions.

  9. Emotion dysregulation and amygdala dopamine D2-type receptor availability in methamphetamine users.

    Okita, Kyoji; Ghahremani, Dara G; Payer, Doris E; Robertson, Chelsea L; Dean, Andy C; Mandelkern, Mark A; London, Edythe D

    2016-04-01

    Individuals who use methamphetamine chronically exhibit emotional and dopaminergic neurochemical deficits. Although the amygdala has an important role in emotion processing and receives dopaminergic innervation, little is known about how dopamine transmission in this region contributes to emotion regulation. This investigation aimed to evaluate emotion regulation in subjects who met DSM-IV criteria for methamphetamine dependence, and to test for a relationship between self-reports of difficulty in emotion regulation and D2-type dopamine receptor availability in the amygdala. Ninety-four methamphetamine-using and 102 healthy-control subjects completed the Difficulties in Emotion Regulation Scale (DERS); 33 of those who used methamphetamine completed the Addiction Severity Index (ASI). A subset of 27 methamphetamine-group and 20 control-group subjects completed positron emission tomography with [(18)F]fallypride to assay amygdala D2-type dopamine receptor availability, measured as binding potential (BPND). The methamphetamine group scored higher than the control group on the DERS total score (pmethamphetamine group. The DERS total score was positively correlated with amygdala BPND in both groups and the combined group of participants (combined: r=0.331, p=0.02), and the groups did not differ in this relationship. These findings highlight problems with emotion regulation linked to methamphetamine use, possibly contributing to personal and interpersonal behavioral problems. They also suggest that D2-type dopamine receptors in the amygdala contribute to emotion regulation in both healthy and methamphetamine-using subjects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Striatal D1- and D2-type dopamine receptors are linked to motor response inhibition in human subjects.

    Robertson, Chelsea L; Ishibashi, Kenji; Mandelkern, Mark A; Brown, Amira K; Ghahremani, Dara G; Sabb, Fred; Bilder, Robert; Cannon, Tyrone; Borg, Jacqueline; London, Edythe D

    2015-04-15

    Motor response inhibition is mediated by neural circuits involving dopaminergic transmission; however, the relative contributions of dopaminergic signaling via D1- and D2-type receptors are unclear. Although evidence supports dissociable contributions of D1- and D2-type receptors to response inhibition in rats and associations of D2-type receptors to response inhibition in humans, the relationship between D1-type receptors and response inhibition has not been evaluated in humans. Here, we tested whether individual differences in striatal D1- and D2-type receptors are related to response inhibition in human subjects, possibly in opposing ways. Thirty-one volunteers participated. Response inhibition was indexed by stop-signal reaction time on the stop-signal task and commission errors on the continuous performance task, and tested for association with striatal D1- and D2-type receptor availability [binding potential referred to nondisplaceable uptake (BPND)], measured using positron emission tomography with [(11)C]NNC-112 and [(18)F]fallypride, respectively. Stop-signal reaction time was negatively correlated with D1- and D2-type BPND in whole striatum, with significant relationships involving the dorsal striatum, but not the ventral striatum, and no significant correlations involving the continuous performance task. The results indicate that dopamine D1- and D2-type receptors are associated with response inhibition, and identify the dorsal striatum as an important locus of dopaminergic control in stopping. Moreover, the similar contribution of both receptor subtypes suggests the importance of a relative balance between phasic and tonic dopaminergic activity subserved by D1- and D2-type receptors, respectively, in support of response inhibition. The results also suggest that the stop-signal task and the continuous performance task use different neurochemical mechanisms subserving motor response inhibition. Copyright © 2015 the authors 0270-6474/15/355990-08$15.00/0.

  11. GABA type a receptor trafficking and the architecture of synaptic inhibition.

    Lorenz-Guertin, Joshua M; Jacob, Tija C

    2018-03-01

    Ubiquitous expression of GABA type A receptors (GABA A R) in the central nervous system establishes their central role in coordinating most aspects of neural function and development. Dysregulation of GABAergic neurotransmission manifests in a number of human health disorders and conditions that in certain cases can be alleviated by drugs targeting these receptors. Precise changes in the quantity or activity of GABA A Rs localized at the cell surface and at GABAergic postsynaptic sites directly impact the strength of inhibition. The molecular mechanisms constituting receptor trafficking to and from these compartments therefore dictate the efficacy of GABA A R function. Here we review the current understanding of how GABA A Rs traffic through biogenesis, plasma membrane transport, and degradation. Emphasis is placed on discussing novel GABAergic synaptic proteins, receptor and scaffolding post-translational modifications, activity-dependent changes in GABA A R confinement, and neuropeptide and neurosteroid mediated changes. We further highlight modern techniques currently advancing the knowledge of GABA A R trafficking and clinically relevant neurodevelopmental diseases connected to GABAergic dysfunction. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 238-270, 2018. © 2017 Wiley Periodicals, Inc.

  12. Herpes simplex virus infection is sensed by both Toll-like receptors and retinoic acid-inducible gene- like receptors, which synergize to induce type I interferon production

    Rasmussen, Simon B; Jensen, Søren B; Nielsen, Christoffer

    2009-01-01

    The innate antiviral response is initiated by pattern recognition receptors, which recognize viral pathogen-associated molecular patterns. Here we show that retinoic acid-inducible gene (RIG)-I-like receptors (RLRs) in cooperation with Toll-like receptor (TLR) 9 is required for expression of type I...... interferons (IFNs) after infection with herpes simplex virus (HSV). Our work also identified RNase L as a critical component in IFN induction. Moreover, we found that TLR9 and RLRs activate distinct, as well as overlapping, intracellular signalling pathways. Thus, RLRs are important for recognition of HSV...

  13. Pharmacological characterization of homobaclofen on wild type and mutant GABA(B)1b receptors coexpressed with the GABA(B)2 receptor

    Jensen, Anders A.; Madsen, Bo E.; Krogsgaard-Larsen, P

    2001-01-01

    homogenate and in an assay of electrically induced contractions of guinea pig ileum. The results from the two tissues did, however, not correlate very well, and in order to further investigate these discrepancies, we have pharmacologically characterized these enantiomers on recombinant wild type and mutant...... rat GABA(B)1b receptors coexpressed with rat GABA(B)2 receptors. The results from this study correlate nicely with the binding data from rat brain. (R)-Homobaclofen was shown to act like (R)-baclofen albeit with 20-fold less potency, and (S)-homobaclofen was inactive on the receptor. The discrepancies...

  14. Application of gamma-aminobutyric acid type A-benzodiazepine receptor imaging for study of neuropsychiatric disorders

    Bao Weiqi; Qiu Chun; Guan Yihui

    2012-01-01

    Gamma-aminobutyric acid type A-benzodiazepine receptors are heterogeneous polypeptide pentamers widely spread in the central nervous system on the neuron membrane. Different subunit combinations educe various neuro-inhibitory pharmacological effects such as sedative, hypnosis, anticonvulsion and anxiolysis. PET can be utilized to study the binding of the receptors in vivo. PET radioligands of gamma-aminobutyric acid type A-benzodiazepine receptors can be classified into 3 types: antagonists,agonists and reverse agonists, of which antagonist radiotracer 11 C-flumazenil is the most commonly applied in epilepsy, anxiety disorders, depression, vegetative state,addiction and other neuro-psychiatric disorders. (authors)

  15. PeaTAR1B: Characterization of a Second Type 1 Tyramine Receptor of the American Cockroach, Periplaneta americana.

    Blenau, Wolfgang; Balfanz, Sabine; Baumann, Arnd

    2017-10-30

    The catecholamines norepinephrine and epinephrine regulate important physiological functions in vertebrates. In insects; these neuroactive substances are functionally replaced by the phenolamines octopamine and tyramine. Phenolamines activate specific guanine nucleotide-binding (G) protein-coupled receptors (GPCRs). Type 1 tyramine receptors are better activated by tyramine than by octopamine. In contrast; type 2 tyramine receptors are almost exclusively activated by tyramine. Functionally; activation of type 1 tyramine receptors leads to a decrease in the intracellular concentration of cAMP ([cAMP] i ) whereas type 2 tyramine receptors can mediate Ca 2+ signals or both Ca 2+ signals and effects on [cAMP] i . Here; we report that the American cockroach ( Periplaneta americana ) expresses a second type 1 tyramine receptor (PeaTAR1B) in addition to PeaTAR1A (previously called PeaTYR1). When heterologously expressed in flpTM cells; activation of PeaTAR1B by tyramine leads to a concentration-dependent decrease in [cAMP] i . Its activity can be blocked by a series of established antagonists. The functional characterization of two type 1 tyramine receptors from P. americana ; PeaTAR1A and PeaTAR1B; which respond to tyramine by changing cAMP levels; is a major step towards understanding the actions of tyramine in cockroach physiology and behavior; particularly in comparison to the effects of octopamine.

  16. PeaTAR1B: Characterization of a Second Type 1 Tyramine Receptor of the American Cockroach, Periplaneta americana

    Wolfgang Blenau

    2017-10-01

    Full Text Available The catecholamines norepinephrine and epinephrine regulate important physiological functions in vertebrates. In insects; these neuroactive substances are functionally replaced by the phenolamines octopamine and tyramine. Phenolamines activate specific guanine nucleotide-binding (G protein-coupled receptors (GPCRs. Type 1 tyramine receptors are better activated by tyramine than by octopamine. In contrast; type 2 tyramine receptors are almost exclusively activated by tyramine. Functionally; activation of type 1 tyramine receptors leads to a decrease in the intracellular concentration of cAMP ([cAMP]i whereas type 2 tyramine receptors can mediate Ca2+ signals or both Ca2+ signals and effects on [cAMP]i. Here; we report that the American cockroach (Periplaneta americana expresses a second type 1 tyramine receptor (PeaTAR1B in addition to PeaTAR1A (previously called PeaTYR1. When heterologously expressed in flpTM cells; activation of PeaTAR1B by tyramine leads to a concentration-dependent decrease in [cAMP]i. Its activity can be blocked by a series of established antagonists. The functional characterization of two type 1 tyramine receptors from P. americana; PeaTAR1A and PeaTAR1B; which respond to tyramine by changing cAMP levels; is a major step towards understanding the actions of tyramine in cockroach physiology and behavior; particularly in comparison to the effects of octopamine.

  17. Immunohistochemistry detected and localized cannabinoid receptor type 2 in bovine fetal pancreas at late gestation

    Cecilia Dall'Aglio

    2017-03-01

    Full Text Available At present, data on the endocannabinoid system expression and distribution in the pancreatic gland appear scarce and controversial as descriptions are limited to humans and laboratory animals. Since the bovine pancreas is very similar to the human in endocrine portion development and control, studies on the fetal gland could prove to be very interesting, as an abnormal maternal condition during late pregnancy may be a predisposing trigger for adult metabolic disorders. The present investigation studied cannabinoid receptor type 2 presence and distribution in the bovine fetal pancreas towards the end of gestation. Histological analyses revealed numerous endocrinal cell clusters or islets which were distributed among exocrine adenomeri in connectival tissue. Immunohistochemistry showed that endocrine-islets contained some CB2-positive cells with a very peculiar localization that is a few primarily localized at the edges of islets and some of them also scattered in the center of the cluster. Characteristically, also the epithelium of the excretory ducts and the smooth muscle layers of the smaller arteries, in the interlobular glandular septa, tested positive for the CB2 endocannabinoid receptor. Conse - quently, the endocannabinoid system, via the cannabinoid receptor type 2, was hypothesized to play a major role in controlling pancreas function from normal fetal development to correct metabolic functioning in adulthood.

  18. Circuit Analysis of a Drosophila Dopamine Type 2 Receptor That Supports Anesthesia-Resistant Memory.

    Scholz-Kornehl, Sabrina; Schwärzel, Martin

    2016-07-27

    Dopamine is central to reinforcement processing and exerts this function in species ranging from humans to fruit flies. It can do so via two different types of receptors (i.e., D1 or D2) that mediate either augmentation or abatement of cellular cAMP levels. Whereas D1 receptors are known to contribute to Drosophila aversive odor learning per se, we here show that D2 receptors are specific for support of a consolidated form of odor memory known as anesthesia-resistant memory. By means of genetic mosaicism, we localize this function to Kenyon cells, the mushroom body intrinsic neurons, as well as GABAergic APL neurons and local interneurons of the antennal lobes, suggesting that consolidated anesthesia-resistant memory requires widespread dopaminergic modulation within the olfactory circuit. Additionally, dopaminergic neurons themselves require D2R, suggesting a critical role in dopamine release via its recognized autoreceptor function. Considering the dual role of dopamine in balancing memory acquisition (proactive function of dopamine) and its "forgetting" (retroactive function of dopamine), our analysis suggests D2R as central player of either process. Dopamine provides different information; while it mediates reinforcement during the learning act (proactive function), it balances memory performance between two antithetic processes thereafter (retroactive function) (i.e., forgetting and augmentation). Such bidirectional design can also be found at level of dopamine receptors, where augmenting D1 and abating D2 receptors are engaged to balance cellular cAMP levels. Here, we report that consolidated anesthesia-resistant memory (ARM), but not other concomitant memory phases, are sensitive to bidirectional dopaminergic signals. By means of genetic mosaicism, we identified widespread dopaminergic modulation within the olfactory circuit that suggests nonredundant and reiterating functions of D2R in support of ARM. Our results oppose ARM to its concomitant memory phases

  19. Enhanced Human-Type Receptor Binding by Ferret-Transmissible H5N1 with a K193T Mutation.

    Peng, Wenjie; Bouwman, Kim M; McBride, Ryan; Grant, Oliver C; Woods, Robert J; Verheije, Monique H; Paulson, James C; de Vries, Robert P

    2018-05-15

    All human influenza pandemics have originated from avian influenza viruses. Although multiple changes are needed for an avian virus to be able to transmit between humans, binding to human-type receptors is essential. Several research groups have reported mutations in H5N1 viruses that exhibit specificity for human-type receptors and promote respiratory droplet transmission between ferrets. Upon detailed analysis, we have found that these mutants exhibit significant differences in fine receptor specificity compared to human H1N1 and H3N2 and retain avian-type receptor binding. We have recently shown that human influenza viruses preferentially bind to α2-6-sialylated branched N-linked glycans, where the sialic acids on each branch can bind to receptor sites on two protomers of the same hemagglutinin (HA) trimer. In this binding mode, the glycan projects over the 190 helix at the top of the receptor-binding pocket, which in H5N1 would create a stearic clash with lysine at position 193. Thus, we hypothesized that a K193T mutation would improve binding to branched N-linked receptors. Indeed, the addition of the K193T mutation to the H5 HA of a respiratory-droplet-transmissible virus dramatically improves both binding to human trachea epithelial cells and specificity for extended α2-6-sialylated N-linked glycans recognized by human influenza viruses. IMPORTANCE Infections by avian H5N1 viruses are associated with a high mortality rate in several species, including humans. Fortunately, H5N1 viruses do not transmit between humans because they do not bind to human-type receptors. In 2012, three seminal papers have shown how these viruses can be engineered to transmit between ferrets, the human model for influenza virus infection. Receptor binding, among others, was changed, and the viruses now bind to human-type receptors. Receptor specificity was still markedly different compared to that of human influenza viruses. Here we report an additional mutation in ferret

  20. Signaling by myeloid C-type lectin receptors in immunity and homeostasis.

    Sancho, David; Reis e Sousa, Caetano

    2012-01-01

    Myeloid cells are key drivers of physiological responses to pathogen invasion or tissue damage. Members of the C-type lectin receptor (CLR) family stand out among the specialized receptors utilized by myeloid cells to orchestrate these responses. CLR ligands include carbohydrate, protein, and lipid components of both pathogens and self, which variably trigger endocytic, phagocytic, proinflammatory, or anti-inflammatory reactions. These varied outcomes rely on a versatile system for CLR signaling that includes tyrosine-based motifs that recruit kinases, phosphatases, or endocytic adaptors as well as nontyrosine-based signals that modulate the activation of other pathways or couple to the uptake machinery. Here, we review the signaling properties of myeloid CLRs and how they impact the role of myeloid cells in innate and adaptive immunity.

  1. The association of metabotropic glutamate receptor type 5 with the neuronal Ca2+-binding protein 2 modulates receptor function.

    Canela, Laia; Fernández-Dueñas, Víctor; Albergaria, Catarina; Watanabe, Masahiko; Lluís, Carme; Mallol, Josefa; Canela, Enric I; Franco, Rafael; Luján, Rafael; Ciruela, Francisco

    2009-10-01

    Metabotropic glutamate (mGlu) receptors mediate in part the CNS effects of glutamate. These receptors interact with a large array of intracellular proteins in which the final role is to regulate receptor function. Here, using co-immunoprecipitation and pull-down experiments we showed a close and specific interaction between mGlu(5) receptor and NECAB2 in both transfected human embryonic kidney cells and rat hippocampus. Interestingly, in pull-down experiments increasing concentrations of calcium drastically reduced the ability of these two proteins to interact, suggesting that NECAB2 binds to mGlu(5) receptor in a calcium-regulated manner. Immunoelectron microscopy detection of NECAB2 and mGlu(5) receptor in the rat hippocampal formation indicated that both proteins are codistributed in the same subcellular compartment of pyramidal cells. In addition, the NECAB2/mGlu(5) receptor interaction regulated mGlu(5b)-mediated activation of both inositol phosphate accumulation and the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway. Overall, these findings indicate that NECAB2 by its physical interaction with mGlu(5b) receptor modulates receptor function.

  2. Plant-derived cannabinoids modulate the activity of transient receptor potential channels of ankyrin type-1 and melastatin type-8.

    De Petrocellis, Luciano; Vellani, Vittorio; Schiano-Moriello, Aniello; Marini, Pietro; Magherini, Pier Cosimo; Orlando, Pierangelo; Di Marzo, Vincenzo

    2008-06-01

    The plant cannabinoids (phytocannabinoids), cannabidiol (CBD), and Delta(9)-tetrahydrocannabinol (THC) were previously shown to activate transient receptor potential channels of both vanilloid type 1 (TRPV1) and ankyrin type 1 (TRPA1), respectively. Furthermore, the endocannabinoid anandamide is known to activate TRPV1 and was recently found to antagonize the menthol- and icilin-sensitive transient receptor potential channels of melastatin type 8 (TRPM8). In this study, we investigated the effects of six phytocannabinoids [i.e., CBD, THC, CBD acid, THC acid, cannabichromene (CBC), and cannabigerol (CBG)] on TRPA1- and TRPM8-mediated increase in intracellular Ca2+ in either HEK-293 cells overexpressing the two channels or rat dorsal root ganglia (DRG) sensory neurons. All of the compounds tested induced TRPA1-mediated Ca2+ elevation in HEK-293 cells with efficacy comparable with that of mustard oil isothiocyanates (MO), the most potent being CBC (EC(50) = 60 nM) and the least potent being CBG and CBD acid (EC(50) = 3.4-12.0 microM). CBC also activated MO-sensitive DRG neurons, although with lower potency (EC(50) = 34.3 microM). Furthermore, although none of the compounds tested activated TRPM8-mediated Ca2+ elevation in HEK-293 cells, they all, with the exception of CBC, antagonized this response when it was induced by either menthol or icilin. CBD, CBG, THC, and THC acid were equipotent (IC(50) = 70-160 nM), whereas CBD acid was the least potent compound (IC(50) = 0.9-1.6 microM). CBG inhibited Ca2+ elevation also in icilin-sensitive DRG neurons with potency (IC(50) = 4.5 microM) similar to that of anandamide (IC(50) = 10 microM). Our findings suggest that phytocannabinoids and cannabis extracts exert some of their pharmacological actions also by interacting with TRPA1 and TRPM8 channels, with potential implications for the treatment of pain and cancer.

  3. NMDA or 5-HT receptor antagonists impair memory reconsolidation and induce various types of amnesia.

    Nikitin, V P; Solntseva, S V; Kozyrev, S A; Nikitin, P V; Shevelkin, A V

    2018-06-01

    Elucidation of amnesia mechanisms is one of the central problems in neuroscience with immense practical application. Previously, we found that conditioned food presentation combined with injection of a neurotransmitter receptor antagonist or protein synthesis inhibitor led to amnesia induction. In the present study, we investigated the time course and features of two amnesias: induced by impairment of memory reconsolidation using an NMDA glutamate receptor antagonist (MK-801) and a serotonin receptor antagonist (methiothepin, MET) on snails trained with food aversion conditioning. During the early period of amnesia (types of amnesia. Retraining an on 1st or 3rd day of amnesia induction facilitated memory formation, i.e. the number of CS + US pairings was lower than at initial training. On the 10th or 30th day after the MET/reminder, the number of CS + US pairings did not change between initial training and retraining. Retraining on the 10th or 30th day following the MK-801/reminder in the same or a new context of learning resulted in short, but not long-term, memory, and the number of CS + US pairings was higher than at the initial training. This type of amnesia was specific to the CS we used at initial training, since long-term memory for another kind of CS could be formed in the same snails. The attained results suggest that disruption of memory reconsolidation using antagonists of serotonin or NMDA glutamate receptors induced amnesias with different abilities to form long-term memory during the late period of development. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Defective membrane expression of human growth hormone (GH) receptor causes Laron-type GH insensitivity syndrome.

    Duquesnoy, P; Sobrier, M L; Amselem, S; Goossens, M

    1991-01-01

    Mutations in the growth hormone receptor (GHR) gene can cause growth hormone (GH) resistance. Given the sequence homology between the extracellular domain of the GHR and a soluble GH-binding protein (GH-BP), it is remarkable that GH-BP binding activity is absent from the serum of patients with Laron-type GH insensitivity, a hereditary form of severe dwarfism. We have previously identified a mutation within the extracellular domain of this receptor, replacing phenylalanine by serine at position 96 of the mature protein, in a patient with Laron syndrome. We have now investigated the effect of this Phe----Ser substitution on hormone binding activity by expressing the total human GHR cDNA and mutant form in eukaryotic cells. The wild-type protein expressed was able to bind GH but no plasma membrane binding was detectable on cells transfected with the mutant cDNA; this was also the case of cells transfected with a Phe96----Ala mutant cDNA, suggesting that the lack of binding activity is not due to a posttranslational modification of serine. Examination of the variant proteins in subcellular fractions revealed the presence of specific GH binding activity in the lysosomal fraction, whereas immunofluorescence studies located mutant proteins in the cytosol. Our findings suggest that these mutant GHRs fail to follow the correct intracellular transport pathway and underline the potential importance of this phenylalanine residue, which is conserved among the GH, prolactin, and erythropoietin receptors that belong to the same cytokine receptor superfamily. Images PMID:1719554

  5. Efficient modulation of γ-aminobutyric acid type A receptors by piperine derivatives.

    Schöffmann, Angela; Wimmer, Laurin; Goldmann, Daria; Khom, Sophia; Hintersteiner, Juliane; Baburin, Igor; Schwarz, Thomas; Hintersteininger, Michael; Pakfeifer, Peter; Oufir, Mouhssin; Hamburger, Matthias; Erker, Thomas; Ecker, Gerhard F; Mihovilovic, Marko D; Hering, Steffen

    2014-07-10

    Piperine activates TRPV1 (transient receptor potential vanilloid type 1 receptor) receptors and modulates γ-aminobutyric acid type A receptors (GABAAR). We have synthesized a library of 76 piperine analogues and analyzed their effects on GABAAR by means of a two-microelectrode voltage-clamp technique. GABAAR were expressed in Xenopus laevis oocytes. Structure-activity relationships (SARs) were established to identify structural elements essential for efficiency and potency. Efficiency of piperine derivatives was significantly increased by exchanging the piperidine moiety with either N,N-dipropyl, N,N-diisopropyl, N,N-dibutyl, p-methylpiperidine, or N,N-bis(trifluoroethyl) groups. Potency was enhanced by replacing the piperidine moiety by N,N-dibutyl, N,N-diisobutyl, or N,N-bistrifluoroethyl groups. Linker modifications did not substantially enhance the effect on GABAAR. Compound 23 [(2E,4E)-5-(1,3-benzodioxol-5-yl)-N,N-dipropyl-2,4-pentadienamide] induced the strongest modulation of GABAA (maximal GABA-induced chloride current modulation (IGABA-max = 1673% ± 146%, EC50 = 51.7 ± 9.5 μM), while 25 [(2E,4E)-5-(1,3-benzodioxol-5-yl)-N,N-dibutyl-2,4-pentadienamide] displayed the highest potency (EC50 = 13.8 ± 1.8 μM, IGABA-max = 760% ± 47%). Compound 23 induced significantly stronger anxiolysis in mice than piperine and thus may serve as a starting point for developing novel GABAAR modulators.

  6. Designing peptide inhibitor of insulin receptor to induce diabetes mellitus type 2 in animal model Mus musculus.

    Permatasari, Galuh W; Utomo, Didik H; Widodo

    2016-10-01

    A designing peptide as agent for inducing diabetes mellitus type 2 (T2DM) in an animal model is challenging. The computational approach provides a sophisticated tool to design a functional peptide that may block the insulin receptor activity. The peptide that able to inhibit the binding between insulin and insulin receptor is a warrant for inducing T2DM. Therefore, we designed a potential peptide inhibitor of insulin receptor as an agent to generate T2DM animal model by bioinformatics approach. The peptide has been developed based on the structure of insulin receptor binding site of insulin and then modified it to obtain the best properties of half life, hydrophobicity, antigenicity, and stability binding into insulin receptor. The results showed that the modified peptide has characteristics 100h half-life, high-affinity -95.1±20, and high stability 28.17 in complex with the insulin receptor. Moreover, the modified peptide has molecular weight 4420.8g/Mol and has no antigenic regions. Based on the molecular dynamic simulation, the complex of modified peptide-insulin receptor is more stable than the commercial insulin receptor blocker. This study suggested that the modified peptide has the promising performance to block the insulin receptor activity that potentially induce diabetes mellitus type 2 in mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Expression of C-type lectin receptor mRNA in chronic otitis media with cholesteatoma.

    Kim, Sang Hoon; Han, Seung-Ho; Byun, Jae Yong; Park, Moon Suh; Kim, Young Il; Yeo, Seung Geun

    2017-06-01

    The levels of expression of various C-type lectin receptors (CLRs) messenger ribo nucleic acids (mRNAs) were significantly higher in cholesteatomas than in normal skin, suggesting that these CLRs may be involved in the pathogenesis of cholesteatoma. Altered expression of pattern recognition receptors may be associated with immune responses in patients with cholesteatoma. This study assessed the levels of expression of CLR mRNAs in normal skin and in cholesteatoma. Cholesteatoma specimens were obtained from 38 patients with acquired cholesteatoma. The levels of expression of various CLR mRNAs were assessed quantitatively using real-time RT-PCR (Reverse transcription polymerase chain reaction) and correlated with age, sex, the presence of bacteria, hearing level, frequency of surgery, and degree of ossicle destruction. The levels of CD206 (cluster of differentiation 206), DEC-205 (Dendritic and epithelial cell-205), MGL (monoacylglycerol lipase), CLEC5A (C-type lectin domain family 5 member A), Dectin-2 (dendrite cell-associated C-type lectin-2), BDCA2 (Blood dendritic cell antigen 2), Mincle, DCIR (dendritic cell immunoreceptor), Dectin-1, MICL (Myeloid inhibitory C type-like lectin), and CLEC12B (C-type lectin domain family 12, member B) mRNAs were significantly higher in cholesteatoma than in control skin samples (p C-type lectin domain family 5 member) and Dectin-1 mRNAs were significantly higher in cholesteatomas with ≥2 than ≤1 destroyed ossicles (p < 0.05), and the levels of MGL, Mincle, Dectin-1, and CLEC12B mRNAs were significantly higher in recurrent than initial cholesteatoma specimens (p < 0.05). The level of CLEC5A mRNAs was significantly higher in patients with severe than mild-to-moderate hearing loss (p < 0.05).

  8. The type 2 cannabinoid receptor regulates susceptibility to osteoarthritis in mice.

    Sophocleous, A; Börjesson, A E; Salter, D M; Ralston, S H

    2015-09-01

    Cannabinoid receptors and their ligands have been implicated in the regulation of various physiological processes but their role in osteoarthritis has not been investigated. The aim of this study was to evaluate the role of the type 2 cannabinoid receptor (Cnr2) in regulating susceptibility to osteoarthritis in mice. We analysed the severity of knee osteoarthritis as assessed by the Osteoarthritis Research Society International (OARSI) scoring system in mice with targeted deletion of Cnr2 (Cnr2(-/-)) and wild type (WT) littermates. Studies were conducted in mice subjected to surgical destabilisation of the medial meniscus (DMM) and in those with spontaneous age-related osteoarthritis (OA). Osteoarthritis was more severe following DMM in the medial compartment of the knee in Cnr2(-/-) compared with WT mice (mean ± sem score = 4.9 ± 0.5 vs 3.6 ± 0.3; P = 0.017). Treatment of WT mice with the CB2-selective agonist HU308 following DMM reduced the severity of OA in the whole joint (HU308 = 8.4 ± 0.2 vs vehicle = 10.4 ± 0.6; P = 0.007). Spontaneous age related osteoarthritis was also more severe in the medial compartment of the knee in 12-month old Cnr2(-/-) mice compared with WT (5.6 ± 0.5 vs 3.5 ± 0.3, P = 0.008). Cultured articular chondrocytes from Cnr2(-/-) mice produced less proteoglycans in vitro than wild type chondrocytes. These studies demonstrate that the Cnr2 pathway plays a role in the pathophysiology of osteoarthritis in mice and shows that pharmacological activation of CB2 has a protective effect. Further studies of the role of cannabinoid receptors in the pathogenesis of osteoarthritis in man are warranted. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  9. Distribution of AMPA-type glutamate receptor subunits in the chick visual system

    Pires R.S.

    1997-01-01

    Full Text Available Several glutamate receptor (GluR subunits have been characterized during the past few years. In the present study, subunit-specific antisera were used to determine the distribution of the AMPA-type glutamate receptor subunits GluR1-4 in retinorecipient areas of the chick brain. Six white leghorn chicks (Gallus gallus, 7-15 days old, unknown sex were deeply anesthetized and perfused with 4% buffered paraformaldehyde and brain sections were stained using immunoperoxidase techniques. The AMPA-type glutamate receptor subunits GluR1, GluR2/3 and GluR4 were present in several retinorecipient areas, with varying degrees of colocalization. For example, perikarya in layers 2, 3, and 5 of the optic tectum contained GluR1, whereas GluR2/3 subunits appeared mainly in neurons of layer 13. The GluR4 subunit was only detected in a few cells of the tectal layer 13. GluR1 and GluR2/3 were observed in neurons of the nucleus geniculatus lateralis ventralis, whereas GluR4 was only present in its neuropil. Somata in the accessory optic nucleus appeared to contain GluR2/3 and GluR4, whereas GluR1 was the dominant subunit in the neuropil of this nucleus. These results suggest that different subpopulations of visual neurons might express different combinations of AMPA-type GluR subunits, which in turn might generate different synaptic responses to glutamate derived from retinal ganglion cell axons

  10. Mesenchymal Stem Cells Sense Three Dimensional Type I Collagen through Discoidin Domain Receptor 1.

    Lund, A W; Stegemann, J P; Plopper, G E

    2009-01-01

    The extracellular matrix provides structural and organizational cues for tissue development and defines and maintains cellular phenotype during cell fate determination. Multipotent mesenchymal stem cells use this matrix to tightly regulate the balance between their differentiation potential and self-renewal in the native niche. When understood, the mechanisms that govern cell-matrix crosstalk during differentiation will allow for efficient engineering of natural and synthetic matrices to specifically direct and maintain stem cell phenotype. This work identifies the discoidin domain receptor 1 (DDR1), a collagen activated receptor tyrosine kinase, as a potential link through which stem cells sense and respond to the 3D organization of their extracellular matrix microenvironment. DDR1 is dependent upon both the structure and proteolytic state of its collagen ligand and is specifically expressed and localized in three dimensional type I collagen culture. Inhibition of DDR1 expression results in decreased osteogenic potential, increased cell spreading, stress fiber formation and ERK1/2 phosphorylation. Additionally, loss of DDR1 activity alters the cell-mediated organization of the naïve type I collagen matrix. Taken together, these results demonstrate a role for DDR1 in the stem cell response to and interaction with three dimensional type I collagen. Dynamic changes in cell shape in 3D culture and the tuning of the local ECM microstructure, directs crosstalk between DDR1 and two dimensional mechanisms of osteogenesis that can alter their traditional roles.

  11. Crystal Structure of the Receptor-Binding Domain of Botulinum Neurotoxin Type HA, Also Known as Type FA or H.

    Yao, Guorui; Lam, Kwok-Ho; Perry, Kay; Weisemann, Jasmin; Rummel, Andreas; Jin, Rongsheng

    2017-03-08

    Botulinum neurotoxins (BoNTs), which have been exploited as cosmetics and muscle-disorder treatment medicines for decades, are well known for their extreme neurotoxicity to humans. They pose a potential bioterrorism threat because they cause botulism, a flaccid muscular paralysis-associated disease that requires immediate antitoxin treatment and intensive care over a long period of time. In addition to the existing seven established BoNT serotypes (BoNT/A-G), a new mosaic toxin type termed BoNT/HA (aka type FA or H) was reported recently. Sequence analyses indicate that the receptor-binding domain (H C ) of BoNT/HA is ~84% identical to that of BoNT/A1. However, BoNT/HA responds differently to some potent BoNT/A-neutralizing antibodies (e.g., CR2) that target the H C . Therefore, it raises a serious concern as to whether BoNT/HA poses a new threat to our biosecurity. In this study, we report the first high-resolution crystal structure of BoNT/HA-H C at 1.8 Å. Sequence and structure analyses reveal that BoNT/HA and BoNT/A1 are different regarding their binding to cell-surface receptors including both polysialoganglioside (PSG) and synaptic vesicle glycoprotein 2 (SV2). Furthermore, the new structure also provides explanations for the ~540-fold decreased affinity of antibody CR2 towards BoNT/HA compared to BoNT/A1. Taken together, these new findings advance our understanding of the structure and function of this newly identified toxin at the molecular level, and pave the way for the future development of more effective countermeasures.

  12. Crystal Structure of the Receptor-Binding Domain of Botulinum Neurotoxin Type HA, Also Known as Type FA or H

    Guorui Yao

    2017-03-01

    Full Text Available Botulinum neurotoxins (BoNTs, which have been exploited as cosmetics and muscle-disorder treatment medicines for decades, are well known for their extreme neurotoxicity to humans. They pose a potential bioterrorism threat because they cause botulism, a flaccid muscular paralysis-associated disease that requires immediate antitoxin treatment and intensive care over a long period of time. In addition to the existing seven established BoNT serotypes (BoNT/A–G, a new mosaic toxin type termed BoNT/HA (aka type FA or H was reported recently. Sequence analyses indicate that the receptor-binding domain (HC of BoNT/HA is ~84% identical to that of BoNT/A1. However, BoNT/HA responds differently to some potent BoNT/A-neutralizing antibodies (e.g., CR2 that target the HC. Therefore, it raises a serious concern as to whether BoNT/HA poses a new threat to our biosecurity. In this study, we report the first high-resolution crystal structure of BoNT/HA-HC at 1.8 Å. Sequence and structure analyses reveal that BoNT/HA and BoNT/A1 are different regarding their binding to cell-surface receptors including both polysialoganglioside (PSG and synaptic vesicle glycoprotein 2 (SV2. Furthermore, the new structure also provides explanations for the ~540-fold decreased affinity of antibody CR2 towards BoNT/HA compared to BoNT/A1. Taken together, these new findings advance our understanding of the structure and function of this newly identified toxin at the molecular level, and pave the way for the future development of more effective countermeasures.

  13. Crystal Structure of the Receptor-Binding Domain of Botulinum Neurotoxin Type HA, Also Known as Type FA or H

    Yao, Guorui; Lam, Kwok-ho; Perry, Kay; Weisemann, Jasmin; Rummel, Andreas; Jin, Rongsheng (Cornell); (Dusseldorf); (UCI)

    2017-03-01

    Botulinum neurotoxins (BoNTs), which have been exploited as cosmetics and muscle-disorder treatment medicines for decades, are well known for their extreme neurotoxicity to humans. They pose a potential bioterrorism threat because they cause botulism, a flaccid muscular paralysis-associated disease that requires immediate antitoxin treatment and intensive care over a long period of time. In addition to the existing seven established BoNT serotypes (BoNT/A–G), a new mosaic toxin type termed BoNT/HA (aka type FA or H) was reported recently. Sequence analyses indicate that the receptor-binding domain (HC) of BoNT/HA is ~84% identical to that of BoNT/A1. However, BoNT/HA responds differently to some potent BoNT/A-neutralizing antibodies (e.g., CR2) that target the HC. Therefore, it raises a serious concern as to whether BoNT/HA poses a new threat to our biosecurity. In this study, we report the first high-resolution crystal structure of BoNT/HA-HC at 1.8 Å. Sequence and structure analyses reveal that BoNT/HA and BoNT/A1 are different regarding their binding to cell-surface receptors including both polysialoganglioside (PSG) and synaptic vesicle glycoprotein 2 (SV2). Furthermore, the new structure also provides explanations for the ~540-fold decreased affinity of antibody CR2 towards BoNT/HA compared to BoNT/A1. Taken together, these new findings advance our understanding of the structure and function of this newly identified toxin at the molecular level, and pave the way for the future development of more effective countermeasures

  14. Local angiotensin II promotes adipogenic differentiation of human adipose tissue mesenchymal stem cells through type 2 angiotensin receptor

    Veronika Y. Sysoeva

    2017-12-01

    Full Text Available Obesity is often associated with high systemic and local activity of renin-angiotensin system (RAS. Mesenchymal stem cells of adipose tissue are the main source of adipocytes. The aim of this study was to clarify how local RAS could control adipose differentiation of human adipose tissue derived mesenchymal stem cells (ADSCs. We examined the distribution of angiotensin receptor expressing cells in human adipose tissue and found that type 1 and type 2 receptors are co-expressed in its stromal compartment, which is known to contain mesenchymal stem cells. To study the expression of receptors specifically in ADSCs we have isolated them from adipose tissue. Up to 99% of cultured ADSCs expressed angiotensin II (AngII receptor type 1 (AT1. Using the analysis of Ca2+ mobilization in single cells we found that only 5.2 ± 2.7% of ADSCs specifically respond to serial Ang II applications via AT1 receptor and expressed this receptor constantly. This AT1const ADSCs subpopulation exhibited increased adipose competency, which was triggered by endogenous AngII. Inhibitory and expression analyses showed that AT1const ADSCs highly co-express AngII type 2 receptor (AT2, which was responsible for increased adipose competency of this ADSC subpopulation.

  15. An Antibody Blocking Activin Type II Receptors Induces Strong Skeletal Muscle Hypertrophy and Protects from Atrophy

    Minetti, Giulia C.; Sheppard, KellyAnn; Ibebunjo, Chikwendu; Feige, Jerome N.; Hartmann, Steffen; Brachat, Sophie; Rivet, Helene; Koelbing, Claudia; Morvan, Frederic; Hatakeyama, Shinji

    2014-01-01

    The myostatin/activin type II receptor (ActRII) pathway has been identified to be critical in regulating skeletal muscle size. Several other ligands, including GDF11 and the activins, signal through this pathway, suggesting that the ActRII receptors are major regulatory nodes in the regulation of muscle mass. We have developed a novel, human anti-ActRII antibody (bimagrumab, or BYM338) to prevent binding of ligands to the receptors and thus inhibit downstream signaling. BYM338 enhances differentiation of primary human skeletal myoblasts and counteracts the inhibition of differentiation induced by myostatin or activin A. BYM338 prevents myostatin- or activin A-induced atrophy through inhibition of Smad2/3 phosphorylation, thus sparing the myosin heavy chain from degradation. BYM338 dramatically increases skeletal muscle mass in mice, beyond sole inhibition of myostatin, detected by comparing the antibody with a myostatin inhibitor. A mouse version of the antibody induces enhanced muscle hypertrophy in myostatin mutant mice, further confirming a beneficial effect on muscle growth beyond myostatin inhibition alone through blockade of ActRII ligands. BYM338 protects muscles from glucocorticoid-induced atrophy and weakness via prevention of muscle and tetanic force losses. These data highlight the compelling therapeutic potential of BYM338 for the treatment of skeletal muscle atrophy and weakness in multiple settings. PMID:24298022

  16. A polycystin-type transient receptor potential (Trp channel that is activated by ATP

    David Traynor

    2017-02-01

    Full Text Available ATP and ADP are ancient extra-cellular signalling molecules that in Dictyostelium amoebae cause rapid, transient increases in cytosolic calcium due to an influx through the plasma membrane. This response is independent of hetero-trimeric G-proteins, the putative IP3 receptor IplA and all P2X channels. We show, unexpectedly, that it is abolished in mutants of the polycystin-type transient receptor potential channel, TrpP. Responses to the chemoattractants cyclic-AMP and folic acid are unaffected in TrpP mutants. We report that the DIF morphogens, cyclic-di-GMP, GABA, glutamate and adenosine all induce strong cytoplasmic calcium responses, likewise independently of TrpP. Thus, TrpP is dedicated to purinergic signalling. ATP treatment causes cell blebbing within seconds but this does not require TrpP, implicating a separate purinergic receptor. We could detect no effect of ATP on chemotaxis and TrpP mutants grow, chemotax and develop almost normally in standard conditions. No gating ligand is known for the human homologue of TrpP, polycystin-2, which causes polycystic kidney disease. Our results now show that TrpP mediates purinergic signalling in Dictyostelium and is directly or indirectly gated by ATP.

  17. A novel polymorphism in the coding region of the vasopressin type 2 receptor gene

    J.L. Rocha

    1997-04-01

    Full Text Available Nephrogenic diabetes insipidus (NDI is a rare disease characterized by renal inability to respond properly to arginine vasopressin due to mutations in the vasopressin type 2 receptor (V2(R gene in affected kindreds. In most kindreds thus far reported, the mode of inheritance follows an X chromosome-linked recessive pattern although autosomal-dominant and autosomal-recessive modes of inheritance have also been described. Studies demonstrating mutations in the V2(R gene in affected kindreds that modify the receptor structure, resulting in a dys- or nonfunctional receptor have been described, but phenotypically indistinguishable NDI patients with a structurally normal V2(R gene have also been reported. In the present study, we analyzed exon 3 of the V2(R gene in 20 unrelated individuals by direct sequencing. A C®T alteration in the third position of codon 331 (AGC®AGT, which did not alter the encoded amino acid, was found in nine individuals, including two unrelated patients with NDI. Taken together, these observations emphasize the molecular heterogeneity of a phenotypically homogeneous syndrome

  18. Purslane Effect on GLP-1 and GLP-1 receptor in type 2 diabetes

    Roja Daliri

    2013-01-01

    Full Text Available Abstract:Background: The aim of this study was to examine the effect of purslane seeds in glucagon-like peptide-1 concentration and glucagon-like peptide-1 receptor in women with diabetes.Methods: This was a quasi-experimental study. The population was consisted of the city of Sari where diabetic women with diabetes II who had no history of using purslane seeds. All individuals used the same dose of metformin under the specialist supervision. Among these individuals, 16 were assigned at random to Purslane group and control group. The purslane group consumed 2.5 grams Purslane with lunch and along with 5 grams of purslane (Portulaca oleracea seeds 7.5 g daily with dinner meals twice daily for 8 weeks. Blood sample was taken before and after 8 weeks, after 12 hours of fasting to 5 ml of the left brachial vein.Results: After 8 weeks using purslane seeds in the experimental group, a significant increase was seen in glucagon-like peptide-1 concentrations (p<0.007, but there was no significant difference in the concentration of glucagon-like peptide-1 receptor (p <0.455. No significant relationship was found between changes in glucagon-like peptide-1 and its receptor.Conclusion: The use of purslane seeds improved Type II diabetes; therefore it can be effective in improving the health of women with diabetes.

  19. Treatment of type 2 diabetes by free Fatty Acid receptor agonists

    Watterson, Kenneth R; Hudson, Brian D; Ulven, Trond

    2014-01-01

    been developed as potential treatments for type 2 diabetes (T2D). In particular, clinical studies show that Fasiglifam, an agonist of the long-chain FFA receptor, FFA1, improved glycemic control and reduced HbA1c levels in T2D patients, with a reduced risk of hypoglycemia. However, this ligand...... was removed from clinical trials due to potential liver toxicity and determining if this is a target or a ligand-specific feature is now of major importance. Pre-clinical studies also show that FFA4 agonism increases insulin sensitivity, induces weight loss, and reduces inflammation and the metabolic and anti...

  20. Lixisenatide, a novel GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus

    Christensen, Mikkel; Knop, Filip K; Holst, Jens J

    2009-01-01

    Lixisenatide, under development by sanofi-aventis, is a novel human glucagon-like peptide-1 receptor (GLP-1R) agonist for the treatment of type 2 diabetes mellitus (T2DM; non-insulin dependent diabetes). The structure of lixisenatide, based on exendin-4(1-39) modified C-terminally with six Lys...... of the anticipated effects of lixisenatide on glycemic measures and weight; favorable results would place lixisenatide for consideration among other GLP-1R agonists in the treatment armamentarium for T2DM....

  1. Imaging of Prostate Cancer Using Urokinase-Type Plasminogen Activator Receptor PET

    Skovgaard, Dorthe; Persson, Morten; Kjaer, Andreas

    2017-01-01

    Urokinase-type plasminogen activator receptor (uPAR) overexpression is an important biomarker for aggressiveness in cancer including prostate cancer (PC) and provides independent clinical information in addition to prostate-specific antigen and Gleason score. This article focuses on uPAR PET...... as a new diagnostic and prognostic imaging biomarker in PC. Many preclinical uPAR-targeted PET imaging studies using AE105 in cancer models have been undertaken with promising results. A major breakthrough was obtained with the recent human translation of uPAR PET in using 64Cu- and 68Ga-labelled versions...

  2. Type 1 IGF receptor translocates to the nucleus of human tumor cells

    Aleksic, Tamara; Chitnis, Meenali M.; Perestenko, Olga V.; Gao, Shan; Thomas, Peter H.; Turner, Gareth D.; Protheroe, Andrew S.; Howarth, Mark; Macaulay, Valentine M.

    2010-01-01

    The type 1 insulin-like growth factor receptor (IGF-1R) is a transmembrane glycoprotein comprising two extracellular α subunits and two β subunits with tyrosine kinase activity. The IGF-1R is frequently upregulated in cancers, and signals from the cell surface to promote proliferation and cell survival. Recent attention has focused on the IGF-1R as a target for cancer treatment. Here we report that the nuclei of human tumor cells contain IGF-1R, detectable using multiple antibodies to α- and ...

  3. The Fifth Transmembrane Domain of Angiotensin II Type 1 Receptor Participates in the Formation of the Ligand-binding Pocket and Undergoes a Counterclockwise Rotation upon Receptor Activation*

    Domazet, Ivana; Martin, Stéphane S.; Holleran, Brian J.; Morin, Marie-Ève; Lacasse, Patrick; Lavigne, Pierre; Escher, Emanuel; Leduc, Richard; Guillemette, Gaétan

    2009-01-01

    The octapeptide hormone angiotensin II exerts a wide variety of cardiovascular effects through the activation of the angiotensin II Type 1 (AT1) receptor, which belongs to the G protein-coupled receptor superfamily. Like other G protein- coupled receptors, the AT1 receptor possesses seven transmembrane domains that provide structural support for the formation of the ligand-binding pocket. The role of the fifth transmembrane domain (TMD5) was investigated using the substituted cysteine accessibility method. All of the residues within Thr-190 to Leu-217 region were mutated one at a time to cysteine, and after expression in COS-7 cells, the mutant receptors were treated with the sulfhydryl-specific alkylating agent methanethiosulfonate-ethylammonium (MTSEA). MTSEA reacts selectively with water-accessible, free sulfhydryl groups of endogenous or introduced point mutation cysteines. If a cysteine is found in the binding pocket, the covalent modification will affect the binding kinetics of the ligand. MTSEA substantially decreased the binding affinity of L197C-AT1, N200C-AT1, I201C-AT1, G203C-AT1, and F204C-AT1 mutant receptors, which suggests that these residues orient themselves within the water-accessible binding pocket of the AT1 receptor. Interestingly, this pattern of acquired MTSEA sensitivity was altered for TMD5 reporter cysteines engineered in a constitutively active N111G-AT1 receptor background. Indeed, mutant I201C-N111G-AT1 became more sensitive to MTSEA, whereas mutant G203C-N111G-AT1 lost some sensitivity. Our results suggest that constitutive activation of AT1 receptor causes an apparent counterclockwise rotation of TMD5 as viewed from the extracellular side. PMID:19773549

  4. The fifth transmembrane domain of angiotensin II Type 1 receptor participates in the formation of the ligand-binding pocket and undergoes a counterclockwise rotation upon receptor activation.

    Domazet, Ivana; Martin, Stéphane S; Holleran, Brian J; Morin, Marie-Eve; Lacasse, Patrick; Lavigne, Pierre; Escher, Emanuel; Leduc, Richard; Guillemette, Gaétan

    2009-11-13

    The octapeptide hormone angiotensin II exerts a wide variety of cardiovascular effects through the activation of the angiotensin II Type 1 (AT(1)) receptor, which belongs to the G protein-coupled receptor superfamily. Like other G protein- coupled receptors, the AT(1) receptor possesses seven transmembrane domains that provide structural support for the formation of the ligand-binding pocket. The role of the fifth transmembrane domain (TMD5) was investigated using the substituted cysteine accessibility method. All of the residues within Thr-190 to Leu-217 region were mutated one at a time to cysteine, and after expression in COS-7 cells, the mutant receptors were treated with the sulfhydryl-specific alkylating agent methanethiosulfonate-ethylammonium (MTSEA). MTSEA reacts selectively with water-accessible, free sulfhydryl groups of endogenous or introduced point mutation cysteines. If a cysteine is found in the binding pocket, the covalent modification will affect the binding kinetics of the ligand. MTSEA substantially decreased the binding affinity of L197C-AT(1), N200C-AT(1), I201C-AT(1), G203C-AT(1), and F204C-AT(1) mutant receptors, which suggests that these residues orient themselves within the water-accessible binding pocket of the AT(1) receptor. Interestingly, this pattern of acquired MTSEA sensitivity was altered for TMD5 reporter cysteines engineered in a constitutively active N111G-AT(1) receptor background. Indeed, mutant I201C-N111G-AT(1) became more sensitive to MTSEA, whereas mutant G203C-N111G-AT(1) lost some sensitivity. Our results suggest that constitutive activation of AT(1) receptor causes an apparent counterclockwise rotation of TMD5 as viewed from the extracellular side.

  5. Interaction of integrin β4 with S1P receptors in S1P- and HGF-induced endothelial barrier enhancement.

    Ni, Xiuqin; Epshtein, Yulia; Chen, Weiguo; Zhou, Tingting; Xie, Lishi; Garcia, Joe G N; Jacobson, Jeffrey R

    2014-06-01

    We previously reported sphingosine 1-phosphate (S1P) and hepatocyte growth factor (HGF) augment endothelial cell (EC) barrier function and attenuate murine acute lung inury (ALI). While the mechanisms underlying these effects are not fully understood, S1P and HGF both transactivate the S1P receptor, S1PR1 and integrin β4 (ITGB4) at membrane caveolin-enriched microdomains (CEMs). In the current study, we investigated the roles of S1PR2 and S1PR3 in S1P/HGF-mediated EC signaling and their associations with ITGB4. Our studies confirmed ITGB4 and S1PR2/3 are recruited to CEMs in human lung EC in response to either S1P (1 µM, 5 min) or HGF (25 ng/ml, 5 min). Co-immunoprecipitation experiments identified an S1P/HGF-mediated interaction of ITGB4 with both S1PR2 and S1PR3. We then employed an in situ proximity ligation assay (PLA) to confirm a direct ITGB4-S1PR3 association induced by S1P/HGF although a direct association was not detectable between S1PR2 and ITGB4. S1PR1 knockdown (siRNA), however, abrogated S1P/HGF-induced ITGB4-S1PR2 associations while there was no effect on ITGB4-S1PR3 associations. Moreover, PLA confirmed a direct association between S1PR1 and S1PR2 induced by S1P and HGF. Finally, silencing of S1PR2 significantly attenuated S1P/HGF-induced EC barrier enhancement as measured by transendothelial resistance while silencing of S1PR3 significantly augmented S1P/HGF-induced barrier enhancement. These results confirm an important role for S1PR2 and S1PR3 in S1P/HGF-mediated EC barrier responses that are associated with their complex formation with ITGB4. Our findings elucidate novel mechanisms of EC barrier regulation that may ultimately lead to new therapeutic targets for disorders characterized by increased vascular permeability including ALI. © 2013 Wiley Periodicals, Inc.

  6. Troglitazone stimulates β-arrestin-dependent cardiomyocyte contractility via the angiotensin II type 1A receptor

    Tilley, Douglas G.; Nguyen, Anny D.; Rockman, Howard A.

    2010-01-01

    Peroxisome proliferator-activated receptor γ (PPARγ) agonists are commonly used to treat cardiovascular diseases, and are reported to have several effects on cardiovascular function that may be due to PPARγ-independent signaling events. Select angiotensin receptor blockers (ARBs) interact with and modulate PPARγ activity, thus we hypothesized that a PPARγ agonist may exert physiologic effects via the angiotensin II type 1 A receptor (AT1 A R). In AT1 A R-overexpressing HEK 293 cells, both angiotensin II (Ang II) and the PPARγ agonist troglitazone (Trog) enhanced AT1 A R internalization and recruitment of endogenous β-arrestin1/2 (βarr1/2) to the AT1 A R. A fluorescence assay to measure diacylglycerol (DAG) accumulation showed that although Ang II induced AT1 A R-G q protein-mediated DAG accumulation, Trog had no impact on DAG generation. Trog-mediated recruitment of βarr1/2 was selective to AT1 A R as the response was prevented by an ARB- and Trog-mediated βarr1/2 recruitment to β1-adrenergic receptor (β1AR) was not observed. In isolated mouse cardiomyocytes, Trog increased both % and rate of cell shortening to a similar extent as Ang II, effects which were blocked with an ARB. Additionally, these effects were found to be βarr2-dependent, as cardiomyocytes isolated from βarr2-KO mice showed blunted contractile responses to Trog. These findings show for the first time that the PPARγ agonist Trog acts at the AT1 A R to simultaneously block G q protein activation and induce the recruitment of βarr1/2, which leads to an increase in cardiomyocyte contractility.

  7. Interactions of pyrethroid insecticides with GABAA and peripheral-type benzodiazepine receptors

    Devaud, L.L.

    1988-01-01

    Pyrethroid insecticides are potent proconvulsants in the rat. All pyrethroids evincing proconvulsant activity elicited a similar 25-30% maximal reduction of seizure threshold. The Type II pyrethroids were the most potent proconvulsants with 1RαS, cis cypermethrin having an ED 50 value of 6.3 nmol/kg. The proconvulsant activity of both Type I and Type II pyrenthroids was blocked by pretreatment with PK 11195, the peripheral-type benzodiazepine receptor (PTBR) antagonist. In contrast, phenytoin did not antagonize the proconvulsant activity of either deltamethrin or permethrin. Pyrethroids displaced the specific binding of [ 3 H]Ro5-4864 to rat brain membranes with a significant correlation between the log EC 50 values for their activities as proconvulsants and the log IC 50 values for their inhibition of [ 3 H]Ro5-4864 binding. Both Ro5-4864 and pyrethroid insecticides were found to influence specific [ 35 S]TBPS binding in a GABA-dependent manner. PK 11195 and the Type II pyrethroid, deltamethrin antagonized the Ro5-4864-induced modulation of [ 35 S]TBPS binding. Pyrethroid insecticides, Ro5-4864 and veratridine influenced GABA-gated 36 Chloride influx. Moreover, the Type II pyrethroids elicited an increase in 36 chloride influx in the absence of GABA-stimulation. Both of these actions were antagonized by PK 11195 and tetrodotoxin

  8. The Angiotensin II Type 1 Receptor Antagonist Losartan Affects NHE1-Dependent Melanoma Cell Behavior

    Daniel Navin Olschewski

    2018-03-01

    Full Text Available Background/Aims: The peptide hormone angiotensin II (ATII plays a prominent role in regulating vasoconstriction and blood pressure. Its primary target is the angiotensin II receptor type 1 (AT1, the stimulation of which induces an increase in cytosolic [Ca2+] and calmodulin activation. Ca2+-bound (activated calmodulin stimulates the activity of the Na+/ H+ exchanger isoform 1 (NHE1; and increased NHE1 activity is known to promote melanoma cell motility. The competitive AT1 receptor inhibitor losartan is often used to lower blood pressure in hypertensive patients. Since AT1 mediates ATII-stimulated NHE1 activity, we set out to investigate whether ATII and losartan have an impact on NHE1-dependent behavior of human melanoma (MV3 cells. Methods: ATII receptor expression was verified by PCR, F-actin was visualized using fluorescently labeled phalloidin, and cytosolic [Ca2+] and pH were determined ratiometrically using Fura-2 and BCECF, respectively. MV3 cell behavior was analyzed using migration, adhesion, invasion and proliferation assays. Results: MV3 cells express both AT1 and the angiotensin II receptor type 2 (AT2. Stimulation of MV3 cells with ATII increased NHE1 activity which could be counteracted by both losartan and the Ca2+/ calmodulin inhibitor ophiobolin-A. ATII stimulation induced a decrease in MV3 cell migration and a more spherical cell morphology accompanied by an increase in the density of F-actin. Independently of the presence of ATII, both NHE1 and migratory activity were reduced when AT1 was blocked by losartan. On the other hand, losartan clearly increased cell adhesion to, and the invasion of, a collagen type I substrate. The AT2 inhibitor PD123319 did not affect NHE1 activity, proliferation and migration, but increased adhesion and invasion. Conclusion: Losartan inhibits NHE1 activity and the migration of human melanoma cells. At the same time, losartan promotes MV3 cell adhesion and invasion. The therapeutic use of AT1

  9. Selective expression of muscarinic acetylcholine receptor subtype M3 by mouse type III taste bud cells.

    Mori, Yusuke; Eguchi, Kohgaku; Yoshii, Kiyonori; Ohtubo, Yoshitaka

    2016-11-01

    Each taste bud cell (TBC) type responds to a different taste. Previously, we showed that an unidentified cell type(s) functionally expresses a muscarinic acetylcholine (ACh) receptor subtype, M3, and we suggested the ACh-dependent modification of its taste responsiveness. In this study, we found that M3 is expressed by type III TBCs, which is the only cell type that possesses synaptic contacts with taste nerve fibers in taste buds. The application of ACh to the basolateral membrane of mouse fungiform TBCs in situ increased the intracellular Ca 2+ concentration in 2.4 ± 1.4 cells per taste bud (mean ± SD, n = 14). After Ca 2+ imaging, we supravitally labeled type II cells (phospholipase C β2 [PLCβ2]-immunoreactive cells) with Lucifer yellow CH (LY), a fluorescent dye and investigated the positional relationship between ACh-responding cells and LY-labeled cells. After fixation, the TBCs were immunohistostained to investigate the positional relationships between immunohistochemically classified cells and LY-labeled cells. The overlay of the two positional relationships obtained by superimposing the LY-labeled cells showed that all of the ACh-responding cells were type III cells (synaptosomal-associated protein 25 [SNAP-25]-immunoreactive cells). The ACh responses required no added Ca 2+ in the bathing solution. The addition of 1 μM U73122, a phospholipase C inhibitor, decreased the magnitude of the ACh response, whereas that of 1 μM U73343, a negative control, had no effect. These results suggest that type III cells respond to ACh and release Ca 2+ from intracellular stores. We also discuss the underlying mechanism of the Ca 2+ response and the role of M3 in type III cells.

  10. Interleukin-1 receptor type I gene-deficient mice are less susceptible to Staphylococcus epidermidis biomaterial-associated infection than are wild-type mice

    Boelens, J. J.; van der Poll, T.; Zaat, S. A.; Murk, J. L.; Weening, J. J.; Dankert, J.

    2000-01-01

    Elevated concentrations of interleukin-1 (IL-1) were found in tissue surrounding biomaterials infected with Staphylococcus epidermidis. To determine the role of IL-1 in biomaterial-associated infection (BAI), IL-1 receptor type I-deficient (IL-1R(-/-)) and wild-type mice received subcutaneous

  11. Comparative effects of chlorpyrifos in wild type and cannabinoid Cb1 receptor knockout mice

    Baireddy, Praveena; Liu, Jing; Hinsdale, Myron; Pope, Carey

    2011-01-01

    Endocannabinoids (eCBs) modulate neurotransmission by inhibiting the release of a variety of neurotransmitters. The cannabinoid receptor agonist WIN 55.212-2 (WIN) can modulate organophosphorus (OP) anticholinesterase toxicity in rats, presumably by inhibiting acetylcholine (ACh) release. Some OP anticholinesterases also inhibit eCB-degrading enzymes. We studied the effects of the OP insecticide chlorpyrifos (CPF) on cholinergic signs of toxicity, cholinesterase activity and ACh release in tissues from wild type (+/+) and cannabinoid CB1 receptor knockout (−/−) mice. Mice of both genotypes (n = 5–6/treatment group) were challenged with CPF (300 mg/kg, 2 ml/kg in peanut oil, sc) and evaluated for functional and neurochemical changes. Both genotypes exhibited similar cholinergic signs and cholinesterase inhibition (82–95% at 48 h after dosing) in cortex, cerebellum and heart. WIN reduced depolarization-induced ACh release in vitro in hippocampal slices from wild type mice, but had no effect in hippocampal slices from knockouts or in striatal slices from either genotype. Chlorpyrifos oxon (CPO, 100 μM) reduced release in hippocampal slices from both genotypes in vitro, but with a greater reduction in tissues from wild types (21% vs 12%). CPO had no significant in vitro effect on ACh release in striatum. CPF reduced ACh release in hippocampus from both genotypes ex vivo, but reduction was again significantly greater in tissues from wild types (52% vs 36%). In striatum, CPF led to a similar reduction (20–23%) in tissues from both genotypes. Thus, while CB1 deletion in mice had little influence on the expression of acute toxicity following CPF, CPF- or CPO-induced changes in ACh release appeared sensitive to modulation by CB1-mediated eCB signaling in a brain-regional manner. -- Highlights: ► C57Bl/6 mice showed dose-related cholinergic toxicity following subcutaneous chlorpyrifos exposure. ► Wild type and cannabinoid CB1 receptor knockout littermates

  12. Comparative effects of chlorpyrifos in wild type and cannabinoid Cb1 receptor knockout mice

    Baireddy, Praveena; Liu, Jing; Hinsdale, Myron; Pope, Carey, E-mail: carey.pope@okstate.edu

    2011-11-15

    Endocannabinoids (eCBs) modulate neurotransmission by inhibiting the release of a variety of neurotransmitters. The cannabinoid receptor agonist WIN 55.212-2 (WIN) can modulate organophosphorus (OP) anticholinesterase toxicity in rats, presumably by inhibiting acetylcholine (ACh) release. Some OP anticholinesterases also inhibit eCB-degrading enzymes. We studied the effects of the OP insecticide chlorpyrifos (CPF) on cholinergic signs of toxicity, cholinesterase activity and ACh release in tissues from wild type (+/+) and cannabinoid CB1 receptor knockout (-/-) mice. Mice of both genotypes (n = 5-6/treatment group) were challenged with CPF (300 mg/kg, 2 ml/kg in peanut oil, sc) and evaluated for functional and neurochemical changes. Both genotypes exhibited similar cholinergic signs and cholinesterase inhibition (82-95% at 48 h after dosing) in cortex, cerebellum and heart. WIN reduced depolarization-induced ACh release in vitro in hippocampal slices from wild type mice, but had no effect in hippocampal slices from knockouts or in striatal slices from either genotype. Chlorpyrifos oxon (CPO, 100 {mu}M) reduced release in hippocampal slices from both genotypes in vitro, but with a greater reduction in tissues from wild types (21% vs 12%). CPO had no significant in vitro effect on ACh release in striatum. CPF reduced ACh release in hippocampus from both genotypes ex vivo, but reduction was again significantly greater in tissues from wild types (52% vs 36%). In striatum, CPF led to a similar reduction (20-23%) in tissues from both genotypes. Thus, while CB1 deletion in mice had little influence on the expression of acute toxicity following CPF, CPF- or CPO-induced changes in ACh release appeared sensitive to modulation by CB1-mediated eCB signaling in a brain-regional manner. -- Highlights: Black-Right-Pointing-Pointer C57Bl/6 mice showed dose-related cholinergic toxicity following subcutaneous chlorpyrifos exposure. Black-Right-Pointing-Pointer Wild type and

  13. Degradation of tissue-type plasminogen activator by human monocyte- derived macrophages is mediated by the mannose receptor and by the low- density lipoprotein receptor-related protein

    Noorman, F.; Braat, E.A.M.; Rijken, D.C.

    1995-01-01

    The balance of tissue-type plasminogen activator (t-PA) production and degradation determines its concentration in blood and tissues. Disturbance of this balance may result in either increased or decreased proteolysis. In the present study, we identified the receptor systems involved in the

  14. The Endothelin Type A Receptor as a Potential Therapeutic Target in Preeclampsia.

    Bakrania, Bhavisha; Duncan, Jeremy; Warrington, Junie P; Granger, Joey P

    2017-02-28

    Preeclampsia (PE) is a disorder of pregnancy typically characterized by new onset hypertension after gestational week 20 and proteinuria. Although PE is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disease remain unclear and treatment options are limited. However, there is increasing evidence to suggest that endothelin-1 (ET-1) plays a critical role in the pathophysiology of PE. Multiple studies report that ET-1 is increased in PE and some studies report a positive correlation between ET-1 and the severity of symptoms. A number of experimental models of PE are also associated with elevated tissue levels of prepro ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 infusion, Tumor necrosis factor (TNF) -α infusion, and Angiotensin II type 1 receptor autoantibody (AT1-AA) infusion) have proven to be susceptible to Endothelin Type A (ET A ) receptor antagonism. While the results are promising, further work is needed to determine whether ET antagonists could provide an effective therapy for the management of preeclampsia.

  15. Renoprotective effects of angiotensin II receptor blockade in type 1 diabetic patients with diabetic nephropathy

    Andersen, S; Tarnow, L; Rossing, P

    2000-01-01

    BACKGROUND: Angiotensin I-converting enzyme (ACE) inhibitors reduce angiotensin II formation and induce bradykinin accumulation. Animal studies suggest that bradykinin may play a role for the effects of ACE inhibition on blood pressure and kidney function. Therefore, we compared the renal and hem...... inhibition is primarily caused by interference in the renin-angiotensin system. Our study suggest that losartan represents a valuable new drug in the treatment of hypertension and proteinuria in type 1 diabetic patients with diabetic nephropathy....... and hemodynamic effects of specific intervention in the renin-angiotensin system by blockade of the angiotensin II subtype-1 receptor to the effect of ACE inhibition. METHODS: A randomized, double-blind, cross-over trial was performed in 16 type 1 diabetic patients (10 men), age 42 +/- 2 years (mean +/- SEM...

  16. Soluble Urokinase-Type Plasminogen Activator Receptor Levels in Patients With Schizophrenia

    Nielsen, Jimmi; Røge, Rasmus; Pristed, Sofie Gry

    2015-01-01

    PAR) is a protein that can be measured in blood samples and reflects the levels of inflammatory activity. It has been associated with mortality and the development of type 2 diabetes and cardiovascular disease. METHODS: suPAR levels in patients with schizophrenia were compared to healthy controls from the Danish......BACKGROUND: The etiology of schizophrenia remains largely unknown but alterations in the immune system may be involved. In addition to the psychiatric symptoms, schizophrenia is also associated with up to 20 years reduction in life span. Soluble urokinase-type plasminogen activator receptor (su...... Blood Donor Study. SuPAR levels were dichotomized at >4.0 ng/ml, which is considered the threshold for low grade inflammation. A multiple logistic regression model was used and adjusted for age, sex, and current smoking. RESULTS: In total we included 1009 subjects, 105 cases with schizophrenia (10...

  17. Primary isolation strain determines both phage type and receptors recognised by Campylobacter jejuni bacteriophages.

    Martine C Holst Sørensen

    Full Text Available In this study we isolated novel bacteriophages, infecting the zoonotic bacterium Campylobacter jejuni. These phages may be used in phage therapy of C. jejuni colonized poultry to prevent spreading of the bacteria to meat products causing disease in humans. Many C. jejuni phages have been isolated using NCTC12662 as the indicator strain, which may have biased the selection of phages. A large group of C. jejuni phages rely on the highly diverse capsular polysaccharide (CPS for infection and recent work identified the O-methyl phosphoramidate modification (MeOPN of CPS as a phage receptor. We therefore chose seven C. jejuni strains each expressing different CPS structures as indicator strains in a large screening for phages in samples collected from free-range poultry farms. Forty-three phages were isolated using C. jejuni NCTC12658, NCTC12662 and RM1221 as host strains and 20 distinct phages were identified based on host range analysis and genome restriction profiles. Most phages were isolated using C. jejuni strains NCTC12662 and RM1221 and interestingly phage genome size (140 kb vs. 190 kb, host range and morphological appearance correlated with the isolation strain. Thus, according to C. jejuni phage grouping, NCTC12662 and NCTC12658 selected for CP81-type phages, while RM1221 selected for CP220-type phages. Furthermore, using acapsular ∆kpsM mutants we demonstrated that phages isolated on NCTC12658 and NCTC12662 were dependent on the capsule for infection. In contrast, CP220-type phages isolated on RM1221 were unable to infect non-motile ∆motA mutants, hence requiring motility for successful infection. Hence, the primary phage isolation strain determines both phage type (CP81 or CP220 as well as receptors (CPS or flagella recognised by the isolated phages.

  18. Small-animal PET imaging of the type 1 and type 2 cannabinoid receptors in a photothrombotic stroke model

    Vandeputte, Caroline; Casteels, Cindy; Koole, Michel; Gerits, Anneleen; Struys, Tom; Veghel, Daisy van; Evens, Nele; Bormans, Guy; Dresselaers, Tom; Himmelreich, Uwe; Lambrichts, Ivo; Laere, Koen van

    2012-01-01

    Recent ex vivo and pharmacological evidence suggests involvement of the endocannabinoid system in the pathophysiology of stroke, but conflicting roles for type 1 and 2 cannabinoid receptors (CB 1 and CB 2 ) have been suggested. The purpose of this study was to evaluate CB 1 and CB 2 receptor binding over time in vivo in a rat photothrombotic stroke model using PET. CB 1 and CB 2 microPET imaging was performed at regular time-points up to 2 weeks after stroke using [ 18 F]MK-9470 and [ 11 C]NE40. Stroke size was measured using MRI at 9.4 T. Ex vivo validation was performed via immunostaining for CB 1 and CB 2 . Immunofluorescent double stainings were also performed with markers for astrocytes (GFAP) and macrophages/microglia (CD68). [ 18 F]MK-9470 PET showed a strong increase in CB 1 binding 24 h and 72 h after stroke in the cortex surrounding the lesion, extending to the insular cortex 24 h after surgery. These alterations were consistently confirmed by CB 1 immunohistochemical staining. [ 11 C]NE40 did not show any significant differences between stroke and sham-operated animals, although staining for CB 2 revealed minor immunoreactivity at 1 and 2 weeks after stroke in this model. Both CB 1 + and CB 2 + cells showed minor immunoreactivity for CD68. Time-dependent and regionally strongly increased CB 1 , but not CB 2 , binding are early consequences of photothrombotic stroke. Pharmacological interventions should primarily aim at CB 1 signalling as the role of CB 2 seems minor in the acute and subacute phases of stroke. (orig.)

  19. Small-animal PET imaging of the type 1 and type 2 cannabinoid receptors in a photothrombotic stroke model

    Vandeputte, Caroline; Casteels, Cindy; Koole, Michel; Gerits, Anneleen [KU Leuven, Division of Nuclear Medicine, Leuven (Belgium); KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); Struys, Tom [Hasselt University, Laboratory of Histology, Biomedical Research Institute, Hasselt (Belgium); KU Leuven, Biomedical NMR Unit, Leuven (Belgium); Veghel, Daisy van; Evens, Nele; Bormans, Guy [KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); KU Leuven, Laboratory of Radiopharmacy, Leuven (Belgium); Dresselaers, Tom; Himmelreich, Uwe [KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); KU Leuven, Biomedical NMR Unit, Leuven (Belgium); Lambrichts, Ivo [Hasselt University, Laboratory of Histology, Biomedical Research Institute, Hasselt (Belgium); Laere, Koen van [KU Leuven, Division of Nuclear Medicine, Leuven (Belgium); KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); UZ Leuven, Division of Nuclear Medicine, Leuven (Belgium)

    2012-11-15

    Recent ex vivo and pharmacological evidence suggests involvement of the endocannabinoid system in the pathophysiology of stroke, but conflicting roles for type 1 and 2 cannabinoid receptors (CB{sub 1} and CB{sub 2}) have been suggested. The purpose of this study was to evaluate CB{sub 1} and CB{sub 2} receptor binding over time in vivo in a rat photothrombotic stroke model using PET. CB{sub 1} and CB{sub 2} microPET imaging was performed at regular time-points up to 2 weeks after stroke using [{sup 18}F]MK-9470 and [{sup 11}C]NE40. Stroke size was measured using MRI at 9.4 T. Ex vivo validation was performed via immunostaining for CB{sub 1} and CB{sub 2}. Immunofluorescent double stainings were also performed with markers for astrocytes (GFAP) and macrophages/microglia (CD68). [{sup 18}F]MK-9470 PET showed a strong increase in CB{sub 1} binding 24 h and 72 h after stroke in the cortex surrounding the lesion, extending to the insular cortex 24 h after surgery. These alterations were consistently confirmed by CB{sub 1} immunohistochemical staining. [{sup 11}C]NE40 did not show any significant differences between stroke and sham-operated animals, although staining for CB{sub 2} revealed minor immunoreactivity at 1 and 2 weeks after stroke in this model. Both CB{sub 1} {sup +} and CB{sub 2} {sup +} cells showed minor immunoreactivity for CD68. Time-dependent and regionally strongly increased CB{sub 1}, but not CB{sub 2}, binding are early consequences of photothrombotic stroke. Pharmacological interventions should primarily aim at CB{sub 1} signalling as the role of CB{sub 2} seems minor in the acute and subacute phases of stroke. (orig.)

  20. Different β-adrenergic receptor density in different rat skeletal muscle fibre types

    Jensen, J.; Dahl, H.A.; Broers, O.

    1995-01-01

    The effects of adrenaline on skeletal muscle differ between fibre types. The aim of the present study was to investigate the β-adrenoceptor density, affinity and subtype in rat skeletal muscles with different fibre type composition. β-Adrenoceptors were determined in cryostat sections to avoid methodological problems with variable recovery, using the non-selective βadrenoceptor ligand [ 3 H]CGP-12177 and β 1 - and β 2 -selective cold ligands CGP 20712A and ICI 118,551. In the presence of protease inhibitors [ 3 H]CGP-12177 binding was stable, saturable, reversible, and displaceable. Scatchard analysis of binding saturation data was compatible with a single class of specific binding sites. Binding site density (B max ) was higher (P -1 ) than in adult extensor digitorum longus (4.74±0.39 fmol x mg protein -1 ), whereas the dissociation constants (K d ), 0.37±0.05 and 0.31±0.04 nM for soleus and extensor digitorum longus, respectively, were not significantly different. For young rats (5-6 weeks), B max was 11.21±0.33 and 5.45±0.11 fmol x mg protein -1 (P d was 0.27±0.02 and 0.24±0.04 nM for soleus and epitrochlearis, respectively. These results correspond to a receptor density of 2 and 1 pmol x g w.wt. -1 in muscles containing mainly type I and type II fibres, respectively. Displacement studies with CGP 20712A and ICI 118,551 were compatible with mainly β 2 -adrenoceptors, but 7-10% β 1 -adrenoceptors were present in both types of muscle. In conclusion, the receptor density is twice as high in muscles containing mainly type I muscle fibres compared to muscles containing mainly type II fibres, and this may explain some of the different effects of adrenaline between the two muscle fibre types. (au)

  1. Type II and III Taste Bud Cells Preferentially Expressed Kainate Glutamate Receptors in Rats.

    Lee, Sang-Bok; Lee, Cil-Han; Kim, Se-Nyun; Chung, Ki-Myung; Cho, Young-Kyung; Kim, Kyung-Nyun

    2009-12-01

    Glutamate-induced cobalt uptake reveals that non-NMDA glutamate receptors (GluRs) are present in rat taste bud cells. Previous studies involving glutamate induced cobalt staining suggest this uptake mainly occurs via kainate type GluRs. It is not known which of the 4 types of taste bud cells express subunits of kainate GluR. Circumvallate and foliate papillae of Sprague-Dawley rats (45~60 days old) were used to search for the mRNAs of subunits of non-NMDA GluRs using RT-PCR with specific primers for GluR1-7, KA1 and KA2. We also performed RT-PCR for GluR5, KA1, PLCbeta2, and NCAM/SNAP 25 in isolated single cells from taste buds. Taste epithelium, including circumvallate or foliate papilla, express mRNAs of GluR5 and KA1. However, non-taste tongue epithelium expresses no subunits of non-NMDA GluRs. Isolated single cell RT-PCR reveals that the mRNAs of GluR5 and KA1 are preferentially expressed in Type II and Type III cells over Type I cells.

  2. Sensory Gating and Alpha-7 Nicotinic Receptor Gene Allelic Variants in Schizoaffective Disorder, Bipolar Type

    Martin, Laura F.; Leonard, Sherry; Hall, Mei-Hua; Tregellas, Jason R.; Freedman, Robert; Olincy, Ann

    2011-01-01

    Objectives Single nucleotide allelic variants in the promoter region of the chromosome 15 alpha-7 acetylcholine nicotinic receptor gene (CHRNA7) are associated with both schizophrenia and the P50 auditory evoked potential sensory gating deficit. The purpose of this study was to determine if CHRNA7 promoter allelic variants are also associated with abnormal P50 ratios in persons with schizoaffective disorder, bipolar type. Methods P50 auditory evoked potentials were recorded in a paired stimulus paradigm in 17 subjects with schizoaffective disorder, bipolar type. The P50 test to conditioning ratio was used as the measure of sensory gating. Mutation screening of the CHRNA7 promoter region was performed on the subjects’ DNA samples. Comparisons to previously obtained data from persons with schizophrenia and controls were made. Results Subjects with schizophrenia, regardless of allele status, had an abnormal mean P50 ratio. Subjects with schizoaffective disorder, bipolar type and a variant allele had an abnormal mean P50 ratio, whereas those schizoaffective subjects with the common alleles had a normal mean P50 ratio. Normal control subjects had a normal mean ratio, but controls with variant alleles had higher P50 ratios. Conclusions In persons with bipolar type schizoaffective disorder, CHRNA7 promoter region allelic variants are linked to the capacity to inhibit the P50 auditory evoked potential and thus are associated with a type of illness genetically and biologically more similar to schizophrenia. PMID:17192894

  3. A single mutation in Taiwanese H6N1 influenza hemagglutinin switches binding to human-type receptors

    de Vries, Robert P.; Tzarum, Netanel; Peng, Wenjie; Thompson, Andrew J.; Ambepitiya Wickramasinghe, Iresha N.; de la Pena, Alba T. Torrents; van Breemen, Marielle J.; Bouwman, Kim M.; Zhu, Xueyong; McBride, Ryan; Yu, Wenli; Sanders, Rogier W.; Verheije, Monique H.; Wilson, Ian A.; Paulson, James C.

    2017-07-10

    In June 2013, the first case of human infection with an avian H6N1 virus was reported in a Taiwanese woman. Although this was a single non-fatal case, the virus continues to circulate in Taiwanese poultry. As with any emerging avian virus that infects humans, there is concern that acquisition of human-type receptor specificity could enable transmission in the human population. Despite mutations in the receptor-binding pocket of the human H6N1 isolate, it has retained avian-type (NeuAcα2-3Gal) receptor specificity. However, we show here that a single nucleotide substitution, resulting in a change from Gly to Asp at position 225 (G225D), completely switches specificity to human-type (NeuAcα2-6Gal) receptors. Significantly, G225D H6 loses binding to chicken trachea epithelium and is now able to bind to human tracheal tissue. Structural analysis reveals that Asp225 directly interacts with the penultimate Gal of the human-type receptor, stabilizing human receptor binding.

  4. Synthesis and Biological Evaluation of Thiophene-Based Cannabinoid Receptor Type 2 Radiotracers for PET Imaging

    Ahmed Haider

    2016-07-01

    Full Text Available Over the past two decades, our understanding of the endocannabinoid system has greatly improved due to the wealth of results obtained from exploratory studies. Currently, two cannabinoid receptor subtypes have been well characterized. The cannabinoid receptor type 1 (CB1 is widely expressed in the central nervous system, while the levels of the cannabinoid receptor type 2 (CB2 in the brain and spinal cord of healthy individuals are relatively low. However, recent studies demonstrated a CB2 upregulation on activated microglia upon neuroinflammation, an indicator of neurodegeneration. Our research group aims to develop a suitable positron emission tomography (PET tracer to visualize the CB2 receptor in patients suffering from neurodegenerative diseases. Herein we report two novel thiophene-based 11C-labeled PET ligands designated [11C]AAT-015 and [11C]AAT-778. The reference compounds were synthesized using Gewald reaction conditions to obtain the aminothiophene intermediates, followed by amide formation. Saponification of the esters provided their corresponding precursors. Binding affinity studies revealed Ki values of 3.3 ± 0.5 nM (CB2 and 1.0 ± 0.2 µM (CB1 for AAT-015. AAT-778 showed similar Ki values of 4.3 ± 0.7 nM (CB2 and 1.1 ± 0.1 µM (CB1. Radiosynthesis was carried out under basic conditions using [11C]iodomethane as methylating agent. After semi-preparative HPLC purification both radiolabeled compounds were obtained in 99% radiochemical purity and the radiochemical yields ranged from 12 to 37%. Specific activity was between 96 - 449 GBq/µmol for both tracers. In order to demonstrate CB2 specificity of [11C]AAT-015 and [11C]AAT-778, we carried out autoradiography studies using CB2-positive mouse/rat spleen tissues. The obtained results revealed unspecific binding in spleen tissue that was not blocked by an excess of CB2-specific ligand GW402833. For in vivo analysis, [11C]AAT-015 was administered to healthy rats via tail

  5. Different serotonin receptor types participate in 5-hydroxytryptophan-induced gonadotropins and prolactin release in the female infantile rat.

    Lacau-Mengido, I M; Libertun, C; Becú-Villalobos, D

    1996-05-01

    Serotonin (5-HT) receptors can be classified into at least three, possibly up to seven, classes of receptors. They comprise the 5-HT1, 5-HT2, and 5-HT3 classes, the "uncloned' 5-HT4 receptor and the recombinant receptors 5-ht5, 5-ht6 and 5-ht7. We investigated the role of different serotonin receptor types in a neuroendocrine response to the activation of the serotonergic system. Female immature rats were chosen as an experimental model as it has been shown that during the 3rd week of life, and not at later developmental stages, 5-hydroxytryptophan (5-HTP, a serotonin precursor) induces gonadotropin release in females and not in males. Besides, at this age, serotonin releases prolactin in both sexes. 5-HTP (50 mg/kg) released prolactin, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as expected. Ketanserin (5-HT2A antagonist) and methysergide (5-HT2C antagonist) blocked 5-HTP-induced prolactin release, but did not block the LH or FSH responses. Ondansetron (5-HT3 receptor antagonist) did not modify prolactin response to 5-HTP, whereas it blocked 5-HTP-induced LH and FSH release. Propranolol (5-HT1 and beta-adrenergic antagonist) blocked prolactin, LH and FSH release induced by 5-HTP. The 5-HT2C agonist 1-(3-chlorophenyl)piperazine dihydrochloride released prolactin, without modifying LH or FSH release. Methyl-quipazine and phenylbiguanide (5-HT3 agonists) increased both LH and FSH levels, without altering prolactin secretion. The present experiments indicate that serotonin acting at the 5-HT3 receptor mediates LH and FSH release in infantile female rats, whereas 5-HT2C or 2A receptor types participate in the release of prolactin at this age. 5-HT1 receptor type may be involved in the release of the three hormones, though a beta-adrenergic component of the response cannot be discarded.

  6. Studying cerebellar circuits by remote control of selected neuronal types with GABA-A receptors

    William Wisden

    2009-12-01

    Full Text Available Although GABA-A receptor-mediated inhibition of cerebellar Purkinje cells by molecular layer interneurons (MLIs has been studied intensely on the cellular level, it has remained unclear how this inhibition regulates cerebellum-dependent behaviour. We have implemented two complementary approaches to investigate the function of the MLI-Purkinje cell synapse on the behavioral level. In the first approach we permanently disrupted inhibitory fast synaptic transmission at the synapse by genetically removing the postsynaptic GABA-A receptors from Purkinje cells (PC-Δγ2 mice. We found that chronic disruption of the MLI-Purkinje cell synapse strongly impaired cerebellar learning of the vestibular occular reflex (VOR, presumably by disrupting the temporal patterns of Purkinje cell activity. However, in PC-Δγ2 mice the baseline VOR reflex was only mildly affected; indeed PC-Δγ2 mice showed no ataxia or gait abnormalities suggesting that MLI control of Purkinje cell activity is either not involved in ongoing motor tasks or that the system has found a way to compensate for its loss. To investigate the latter possibility we have developed an alternative genetic technique; we made the MLI-Purkinje cell synapse selectively sensitive to rapid manipulation with the GABAA receptor modulator zolpidem (PC-γ2-swap mice. Minutes after intraperitoneal zolpidem injection, these PC-γ2-swap mice developed severe motor abnormalities, revealing a substantial contribution of the MLI-Purkinje cell synapse to real time motor control. The cell-type selective permanent knockout of synaptic GABAergic input, and the fast reversible modulation of GABAergic input at the same synapse illustrate how pursuing both strategies gives a fuller view.

  7. Immunocytochemical evidence for co-expression of Type III IP3 receptor with signaling components of bitter taste transduction

    Kinnamon Sue C

    2001-04-01

    Full Text Available Abstract Background Taste receptor cells are responsible for transducing chemical stimuli into electrical signals that lead to the sense of taste. An important second messenger in taste transduction is IP3, which is involved in both bitter and sweet transduction pathways. Several components of the bitter transduction pathway have been identified, including the T2R/TRB taste receptors, phospholipase C β2, and the G protein subunits α-gustducin, β3, and γ13. However, the identity of the IP3 receptor subtype in this pathway is not known. In the present study we used immunocytochemistry on rodent taste tissue to identify the IP3 receptors expressed in taste cells and to examine taste bud expression patterns for IP3R3. Results Antibodies against Type I, II, and III IP3 receptors were tested on sections of rat and mouse circumvallate papillae. Robust cytoplasmic labeling for the Type III IP3 receptor (IP3R3 was found in a large subset of taste cells in both species. In contrast, little or no immunoreactivity was seen with antibodies against the Type I or Type II IP3 receptors. To investigate the potential role of IP3R3 in bitter taste transduction, we used double-label immunocytochemistry to determine whether IP3R3 is expressed in the same subset of cells expressing other bitter signaling components. IP3R3 immunoreactive taste cells were also immunoreactive for PLCβ2 and γ13. Alpha-gustducin immunoreactivity was present in a subset of IP3R3, PLCβ2, and γ13 positive cells. Conclusions IP3R3 is the dominant form of the IP3 receptor expressed in taste cells and our data suggest it plays an important role in bitter taste transduction.

  8. Elucidating determinants of aerosol composition through particle-type-based receptor modeling

    McGuire, M. L.; Jeong, C.-H.; Slowik, J. G.; Chang, R. Y.-W.; Corbin, J. C.; Lu, G.; Mihele, C.; Rehbein, P. J. G.; Sills, D. M. L.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

    2011-08-01

    An aerosol time-of-flight mass spectrometer (ATOFMS) was deployed at a semi-rural site in southern Ontario to characterize the size and chemical composition of individual particles. Particle-type-based receptor modelling of these data was used to investigate the determinants of aerosol chemical composition in this region. Individual particles were classified into particle-types and positive matrix factorization (PMF) was applied to their temporal trends to separate and cross-apportion particle-types to factors. The extent of chemical processing for each factor was assessed by evaluating the internal and external mixing state of the characteristic particle-types. The nine factors identified helped to elucidate the coupled interactions of these determinants. Nitrate-laden dust was found to be the dominant type of locally emitted particles measured by ATOFMS. Several factors associated with aerosol transported to the site from intermediate local-to-regional distances were identified: the Organic factor was associated with a combustion source to the north-west; the ECOC Day factor was characterized by nearby local-to-regional carbonaceous emissions transported from the south-west during the daytime; and the Fireworks factor consisted of pyrotechnic particles from the Detroit region following holiday fireworks displays. Regional aerosol from farther emissions sources was reflected through three factors: two Biomass Burning factors and a highly chemically processed Long Range Transport factor. The Biomass Burning factors were separated by PMF due to differences in chemical processing which were in part elucidated by the passage of two thunderstorm gust fronts with different air mass histories. The remaining two factors, ECOC Night and Nitrate Background, represented the night-time partitioning of nitrate to pre-existing particles of different origins. The distinct meteorological conditions observed during this month-long study in the summer of 2007 provided a unique

  9. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

    Wang, Xianwei; Lu, Jingjun; Khaidakov, Magomed; Mitra, Sona; Ding, Zufeng; Raina, Sameer; Goyal, Tanu; Mehta, Jawahar L.

    2012-01-01

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22 phox , p47 phox , p67 phox , NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H 2 O 2 . Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac fibroblast growth and collagen

  10. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

    Wang, Xianwei, E-mail: XWang2@UAMS.edu; Lu, Jingjun; Khaidakov, Magomed; Mitra, Sona; Ding, Zufeng; Raina, Sameer; Goyal, Tanu; Mehta, Jawahar L., E-mail: MehtaJL@UAMS.edu

    2012-03-15

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22{sup phox}, p47{sup phox}, p67{sup phox}, NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H{sub 2}O{sub 2}. Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac

  11. Type I and type II interferons upregulate functional type I interleukin-1 receptor in a human fibroblast cell line TIG-1.

    Takii, T; Niki, N; Yang, D; Kimura, H; Ito, A; Hayashi, H; Onozaki, K

    1995-12-01

    The regulation of type I interleukin-1 receptor (IL-1R) expression by type I, interferon (IFN)-alpha A/D, and type II IFN, IFN-gamma, in a human fibroblast cell line TIG-1 was investigated. After 2 h stimulation with human IFN-alpha A/D or IFN-gamma, the levels of type I IL-1R mRNA increased. We previously reported that IL-1 upregulates transcription and cell surface molecules of type I IL-1R in TIG-1 cells through induction of prostaglandin (PG) E2 and cAMP accumulation. However, indomethacin was unable to inhibit the effect of IFNs, indicating that IFNs augment IL-1R expression through a pathway distinct from that of IL-1. The augmentation was also observed in other fibroblast cell lines. Nuclear run-on assays and studies of the stability of mRNA suggested that the increase in IL-1R mRNA was a result of the enhanced transcription of IL-1R gene. Binding studies using 125I-IL-1 alpha revealed that the number of cell surface IL-1R increased with no change in binding affinity by treatment with these IFNs. Pretreatment of the cells with IFNs enhanced IL-1-induced IL-6 production, indicating that IFNs upregulate functional IL-1R. IL-1 and IFNs are produced by the same cell types, as well as by the adjacent different cell types, and are concomitantly present in lesions of immune and inflammatory reactions. These results therefore suggest that IFNs exhibit synergistic effects with IL-1 through upregulation of IL-1R. Augmented production of IL-6 may also contribute to the reactions.

  12. Cholinergic nicotinic and muscarinic receptors in dementia of Alzheimer, Parkinson and Lewy body types.

    Perry, E K; Smith, C J; Court, J A; Perry, R H

    1990-01-01

    Cholinergic nicotinic and muscarinic receptor binding were measured in post mortem human brain tissue, using low (nM) concentrations of (3H)-nicotine to detect predominately the high affinity nicotinic site and (3H)-N-methylscopolamine in the presence and absence of 3 x 10(-4) M carbachol to measure both the low and high affinity agonist subtypes of the muscarinic receptor group. Consistent with most previous reports, the nicotinic but not muscarinic binding was reduced in the different forms of dementia associated with cortical cholinergic deficits, including Alzheimer's and Parkinson's disease, senile dementia of Lewy body type (SDLT) and Down's syndrome (over 50 years). Analysis of (3H)-nicotine binding displaced by a range of carbachol concentrations (10(-9)-10(-3) M) indicated 2 binding sites for nicotine and that the high affinity rather than low affinity site was reduced in Alzheimer's disease. In all 3 cortical areas investigated (temporal, parietal and occipital) there were increases in the low affinity muscarinic site in Parkinson's disease and SDLT but not Alzheimer's disease or middle-aged Down's syndrome. This observation raised the question of whether the presence of neurofibrillary tangles (evident in the latter but not former 2 disorders) is incompatible with denervation-induced muscarinic supersensitivity in cholinoceptive neurons which include cortical pyramids generally affeted by tangle formation.

  13. Aldosterone downregulates delayed rectifier potassium currents through an angiotensin type 1 receptor-dependent mechanism.

    Lv, Yankun; Wang, Yanjun; Zhu, Xiaoran; Zhang, Hua

    2018-01-01

    We have previously shown that aldosterone downregulates delayed rectifier potassium currents (I Ks ) via activation of the mineralocorticoid receptor (MR) in adult guinea pig cardiomyocytes. Here, we investigate whether angiotensin II/angiotensin type 1 receptor (AngII/AT1R) and intracellular calcium also play a role in these effects. Ventricular cardiomyocytes were isolated from adult guinea pigs and incubated with aldosterone (1 μmol·L -1 ) either alone or in combination with enalapril (1 μmol·L -1 ), losartan (1 μmol·L -1 ), nimodipine (1 μmol·L -1 ), or BAPTA-AM (2.5 μmol·L -1 ) for 24 h. We used the conventional whole cell patch-clamp technique to record the I Ks component. In addition, we evaluated expression of the I Ks subunits KCNQ1 and KCNE1 using Western blotting. Our results showed that both enalapril and losartan, but not nimodipine or BAPTA-AM, completely reversed the aldosterone-induced inhibition of I Ks and its effects on KCNQ1/KCNE1 protein levels. Furthermore, we found that AngII/AT1R mediates the inhibitory effects of aldosterone on I Ks . Finally, the downregulation of I Ks induced by aldosterone did not occur secondarily to a change in intracellular calcium concentrations. Taken together, our findings demonstrate that crosstalk between MR and AT1R underlies the effects of aldosterone, and provide new insights into the mechanism underlying potassium channels.

  14. Nutrient Induced Type 2 and Chemical Induced Type 1 Experimental Diabetes Differently Modulate Gastric GLP-1 Receptor Expression

    Olga Bloch

    2015-01-01

    Full Text Available T2DM patients demonstrate reduced GLP-1 receptor (GLP-1R expression in their gastric glands. Whether induced T2DM and T1DM differently affect the gastric GLP-1R expression is not known. This study assessed extrapancreatic GLP-1R system in glandular stomach of rodents with different types of experimental diabetes. T2DM and T1DM were induced in Psammomys obesus (PO by high-energy (HE diet and by streptozotocin (STZ in Sprague Dawly (SD rats, respectively. GLP-1R expression was determined in glandular stomach by RT PCR and immunohistomorphological analysis. The mRNA expression and cellular association of the GLP-1R in principal glands were similar in control PO and SD rats. However, nutrient and chemical induced diabetes resulted in opposite alterations of glandular GLP-1R expression. Diabetic PO demonstrated increased GLP-1R mRNA expression, intensity of cellular GLP-1R immunostaining, and frequency of GLP-1R positive cells in the neck area of principal glands compared with controls. In contrast, SD diabetic rats demonstrated decreased GLP-1 mRNA, cellular GLP-1R immunoreactivity, and frequency of GLP-1R immunoreactive cells in the neck area compared with controls. In conclusion, nutrient and chemical induced experimental diabetes result in distinct opposite alterations of GLP-1R expression in glandular stomach. These results suggest that induced T1DM and T2DM may differently modulate GLP-1R system in enteropancreatic axis.

  15. Chimeric Feline Coronaviruses That Encode Type II Spike Protein on Type I Genetic Background Display Accelerated Viral Growth and Altered Receptor Usage▿

    Tekes, Gergely; Hofmann-Lehmann, Regina; Bank-Wolf, Barbara; Maier, Reinhard; Thiel, Heinz-Jürgen; Thiel, Volker

    2010-01-01

    Persistent infection of domestic cats with feline coronaviruses (FCoVs) can lead to a highly lethal, immunopathological disease termed feline infectious peritonitis (FIP). Interestingly, there are two serotypes, type I and type II FCoVs, that can cause both persistent infection and FIP, even though their main determinant of host cell tropism, the spike (S) protein, is of different phylogeny and displays limited sequence identity. In cell culture, however, there are apparent differences. Type II FCoVs can be propagated to high titers by employing feline aminopeptidase N (fAPN) as a cellular receptor, whereas the propagation of type I FCoVs is usually difficult, and the involvement of fAPN as a receptor is controversial. In this study we have analyzed the phenotypes of recombinant FCoVs that are based on the genetic background of type I FCoV strain Black but encode the type II FCoV strain 79-1146 S protein. Our data demonstrate that recombinant FCoVs expressing a type II FCoV S protein acquire the ability to efficiently use fAPN for host cell entry and corroborate the notion that type I FCoVs use another main host cell receptor. We also observed that recombinant FCoVs display a large-plaque phenotype and, unexpectedly, accelerated growth kinetics indistinguishable from that of type II FCoV strain 79-1146. Thus, the main phenotypic differences for type I and type II FCoVs in cell culture, namely, the growth kinetics and the efficient usage of fAPN as a cellular receptor, can be attributed solely to the FCoV S protein. PMID:19906918

  16. Efficacy and Safety of GLP-1 Receptor Agonists for Type 2 Diabetes Mellitus Treatment: Systematic Review

    Ana Paula Martins

    2016-04-01

    Full Text Available Introduction: Glucagon-like peptide analogues are a new class of drugs used in the treatment of type 2 diabetes mellitus that mimic the endogenous hormone glucagon-like peptide 1. Glucagon-like peptide 1 regulates glucose levels by stimulating glucose-dependent insulin secretion, suppressing glucagon secretion, delayed gastric emptying and promoting satiety. The individualized treatment of type 2 diabetes mellitus, using various glucagon--like peptide receptor agonists, has recently been described and the interest related to these drugs continues to grow. Objectives: To review the efficacy and safety of glucagon-like peptide 1 agonists in patients with inadequately controlled type 2 diabetes mellitus on metformin alone, highlighting their added value in therapeutic use comparatively to second line oral therapies used in type 2 diabetes mellitus. Methods: Studies were obtained from electronic searches of The Cochrane Library and PubMed. Randomized controlled trials were selected if they were at least 8 weeks in duration; compared a glucagon-like peptide 1 analogue with an oral anti-diabetic agent in patients experiencing inadequate glycemic control with metformin monotherapy; and reported hemoglobin A1c data in non-pregnant adults with type 2 diabetes mellitus. Results: Of 72 potentially relevant articles identified, 23 were retrieved for detailed evaluation and 10 met the inclusion criteria. The majority of glucagon-like peptide 1 agonists showed equivalent or superior efficacy than most active comparators for reducing hemoglobin A1c, with a greater proportion of patients achieving hemoglobin A1c <7%. Glucagon-like peptide 1 agonists also showed extra-glycemic effects such as weight loss and the reduction of important cardiovascular parameters. Side effects included gastrointestinal complications, mainly nausea, vomiting and diarrhea. The incidence of hypoglycemia was less common for this class of agents. Conclusion: Glucagon-like peptide 1

  17. Endoglin-mediated suppression of prostate cancer invasion is regulated by activin and bone morphogenetic protein type II receptors.

    Michael J Breen

    Full Text Available Mortality from prostate cancer (PCa is due to the formation of metastatic disease. Understanding how that process is regulated is therefore critical. We previously demonstrated that endoglin, a type III transforming growth factor β (TGFβ superfamily receptor, suppresses human PCa cell invasion and metastasis. Endoglin-mediated suppression of invasion was also shown by us to be dependent upon the type I TGFβ receptor, activin receptor-like kinase 2 (ALK2, and the downstream effector, Smad1. In this study we demonstrate for the first time that two type II TGFβ receptors are required for endoglin-mediated suppression of invasion: activin A receptor type IIA (ActRIIA and bone morphogenetic protein receptor type II (BMPRII. Downstream signaling through these receptors is predominantly mediated by Smad1. ActRIIA stimulates Smad1 activation in a kinase-dependent manner, and this is required for suppression of invasion. In contrast BMPRII regulates Smad1 in a biphasic manner, promoting Smad1 signaling through its kinase domain but suppressing it through its cytoplasmic tail. BMPRII's Smad1-regulatory effects are dependent upon its expression level. Further, its ability to suppress invasion is independent of either kinase function or tail domain. We demonstrate that ActRIIA and BMPRII physically interact, and that each also interacts with endoglin. The current findings demonstrate that both BMPRII and ActRIIA are necessary for endoglin-mediated suppression of human PCa cell invasion, that they have differential effects on Smad1 signaling, that they make separate contributions to regulation of invasion, and that they functionally and physically interact.

  18. Human erythrocytes bind and inactivate type 5 adenovirus by presenting Coxsackie virus-adenovirus receptor and complement receptor 1

    Carlisle, R. C.; Di, Y.; Cerny, A. M.; Sonnen, A. F. P.; Sim, R. B.; Green, N. K.; Šubr, Vladimír; Ulbrich, Karel; Gilbert, R. J. C.; Fisher, K. D.; Finberg, R. W.; Seymour, L. W.

    2009-01-01

    Roč. 113, č. 9 (2009), s. 1909-1918 ISSN 0006-4971 EU Projects: European Commission(XE) 512087 - GIANT Institutional research plan: CEZ:AV0Z40500505 Keywords : adenovirus * erythrocyte * complement receptor 1 Subject RIV: CD - Macromolecular Chemistry Impact factor: 10.555, year: 2009

  19. Cell-Type-Specific Regulation of the Retinoic Acid Receptor Mediated by the Orphan Nuclear Receptor TLX†

    Kobayashi, Mime; Yu, Ruth T.; Yasuda, Kunio; Umesono, Kazuhiko

    2000-01-01

    Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor β (RARβ). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARβ2 promoter. The region surrounding the transcription start site of the avian RARβ2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARβ2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARβ gene in the eye. PMID:11073974

  20. Cell-type-specific regulation of the retinoic acid receptor mediated by the orphan nuclear receptor TLX.

    Kobayashi, M; Yu, R T; Yasuda, K; Umesono, K

    2000-12-01

    Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor beta (RARbeta). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARbeta2 promoter. The region surrounding the transcription start site of the avian RARbeta2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARbeta2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARbeta gene in the eye.

  1. Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2014-01-01

    Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone, secreted in response to ingestion of nutrients, and has important effects on several of the pathophysiological features of type 2 diabetes (T2D). The effects include potentiation of insulin secretion, suppression of glucagon secretion...... effects. This review gives an overview of the clinical data on GLP-1R agonists that have been compared in head-to-head studies and focuses on relevant differences between the compounds. Highlighting these similarities and differences could be beneficial for physicians in choosing the best treatment......, slowing of gastric emptying and suppression of appetite. In circulation, GLP-1 has a half-life of approximately 2min due to rapid degradation by the enzyme dipeptidyl peptidase 4 (DPP-4). Because of this short half-life GLP-1 receptor (GLP-1R) agonists, resistant to degradation by DPP-4 have been...

  2. Treatment potential of the GLP-1 receptor agonists in type 2 diabetes mellitus

    Østergaard, L; Frandsen, Christian S.; Madsbad, S

    2016-01-01

    Over the last decade, the discovery of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) has increased the treatment options for patients with type 2 diabetes mellitus (T2DM). GLP-1 RAs mimic the effects of native GLP-1, which increases insulin secretion, inhibits glucagon secretion, increases...... satiety and slows gastric emptying. This review evaluates the phase III trials for all approved GLP-1 RAs and reports that all GLP-1 RAs decrease HbA1c, fasting plasma glucose, and lead to a reduction in body weight in the majority of trials. The most common adverse events are nausea and other...... gastrointestinal discomfort, while hypoglycaemia is rarely reported when GLP-1 RAs not are combined with sulfonylurea or insulin. Treatment options in the near future will include co-formulations of basal insulin and a GLP-1 RA....

  3. Angiotensin II Type 2 Receptor Agonist Experts Sustained Neuroprotective Effects In Aged Rats

    Sumners, Colin; Isenberg, Jacob; Harmel, Allison

    2016-01-01

    OBJECTIVE: The renin angiotensin system is a promising target for stroke neuroprotection and therapy through activation of angiotensin type II receptors (AT2R). The selective non-peptide AT2R agonist, Compound 21 (C21), has been shown to exhibit neuroprotection and improve stroke outcomes...... in preclinical studies, effects that likely involve neurotropic actions. However, these beneficial actions of C21 have not been demonstrated to occur beyond 1 week post stroke. The objective of this study was to determine if systemic administration of C21 would exert sustained neuroprotective effects in aged...... min), 24 h, and 48 h after stroke. Infarct size was assessed by magnetic resonance imaging at 21 days post MCAO. Animals received blinded neurological exams at 4 h, 24 h, 72 h, 7d, 14d, and 21d post-MCAO. RESULTS: Systemic treatment with C21 after stroke significantly improved neurological function...

  4. PET imaging of urokinase-type plasminogen activator receptor (uPAR) in prostate cancer

    Skovgaard, Dorthe; Persson, Morten; Kjaer, Andreas

    2016-01-01

    Overexpression of urokinase-type plasminogen activator receptors (uPAR) represents an important biomarker for aggressiveness in most common malignant diseases, including prostate cancer (PC). Accordingly, uPAR expression either assessed directly in malignant PC tissue or assessed directly in plasma...... and prognostic imaging method. In this review, we will focus on the recent development of uPAR PET and the relevance within prostate cancer imaging. Novel antibody and small-molecule radiotracers-targeting uPAR, including a series of uPAR-targeting PET ligands, based on the high affinity peptide ligand AE105......, have been synthesized and tested in vitro and in vivo in preclinical murine xenograft models and, recently, in a first-ever clinical uPAR PET study in cancer patients, including patients with PC. In this phase I study, a high and specific uptake of the tracer 64Cu-DOTA-AE105 was found in both primary...

  5. Quantitative Expression of C-Type Lectin Receptors in Humans and Mice

    Lech, Maciej; Susanti, Heni Eka; Römmele, Christoph; Gröbmayr, Regina; Günthner, Roman; Anders, Hans-Joachim

    2012-01-01

    C-type lectin receptors and their adaptor molecules are involved in the recognition of glycosylated self-antigens and pathogens. However, little is known about the species- and organ-specific expression profiles of these molecules. We therefore determined the mRNA expression levels of Dectin-1, MR1, MR2, DC-SIGN, Syk, Card-9, Bcl-10, Malt-1, Src, Dec-205, Galectin-1, Tim-3, Trem-1, and DAP-12 in 11 solid organs of human and mice. Mouse organs revealed lower mRNA levels of most molecules compared to spleen. However, Dec-205 and Galectin-1 in thymus, Src in brain, MR2, Card-9, Bcl-10, Src, and Dec-205 in small intestine, MR2, Bcl-10, Src, Galectin-1 in kidney, and Src and Galectin-1 in muscle were at least 2-fold higher expressed compared to spleen. Human lung, liver and heart expressed higher mRNA levels of most genes compared to spleen. Dectin-1, MR1, Syk and Trem-1 mRNA were strongly up-regulated upon ischemia-reperfusion injury in murine kidney. Tim3, DAP-12, Card-9, DC-SIGN and MR2 were further up-regulated during renal fibrosis. Murine kidney showed higher DAP-12, Syk, Card-9 and Dectin-1 mRNA expression during the progression of lupus nephritis. Thus, the organ-, and species-specific expression of C-type lectin receptors is different between mice and humans which must be considered in the interpretation of related studies. PMID:22949850

  6. Differential expression of AMPA-type glutamate receptor subunits during development of the chick optic tectum

    Batista S.S.

    2002-01-01

    Full Text Available Glutamate receptors have been often associated with developmental processes. We used immunohistochemical techniques to evaluate the expression of the AMPA-type glutamate receptor (GluR subunits in the chick optic tectum (TeO. Chick embryos from the 5th through the 20th embryonic day (E5-E20 and one-day-old (P1 chicks were used. The three types of immunoreactivity evaluated (GluR1, GluR2/3, and GluR4 had different temporal and spatial expression patterns in the several layers of the TeO. The GluR1 subunit first appeared as moderate staining on E7 and then increased on E9. The mature GluR1 pattern included intense staining only in layer 5 of the TeO. The GluR2/3 subunits presented low expression on E5, which became intense on E7. The staining for GluR2/3 changed to very intense on E14 in tectal layer 13. Staining of layer 13 neurons is the most prominent feature of GluR immunoreactivity in the adult TeO. The GluR4 subunit generally presented the lowest expression starting on E7, which was similar to the adult pattern. Some instances of transient expression of GluR subunits were observed in specific cell populations from E9 through E20. These results demonstrate a differential expression of the GluR subunits in the embryonic TeO, adding information about their possible functions in the developmental processes of the visual system.

  7. Histamine type I (H1) receptor radioligand binding studies on normal T cell subsets, B cells, and monocytes

    Cameron, W.; Doyle, K.; Rocklin, R.E.

    1986-01-01

    A single, specific binding site for [ 3 H]pyrilamine on normal human T helper, T suppressor, B cells, and monocytes was documented. The binding of the radioligand to its receptor is reversible with cold H 1 antagonist, saturates at 40 to 60 nM, and binding equilibrium is achieved in 2 to 4 min. Using a computer program (Ligand), the authors calculated the dissociation constants, binding capacities, and numbers of receptors per cell for each of the different cell types. Monocytes were found to have the highest affinity for [ 3 H]pyrilamine, followed by T helper cells, B cells and T suppressor cells (K/sub D/ = 44.6 +/- 49.4 nM). T suppressor cells were found to express the higher number of H 1 receptors per cell followed by B cells, T helper cells, and monocytes. The binding affinity for [ 3 H]pyrilamine increased over a 48-hr period, whereas the number of receptors per T cell was essentially unchanged. In contrast, T cells stimulated with Con A or PHA were shown to have a greater than fourfold increase in the number of receptors per cell, whereas the binding affinity for [ 3 H]pyrilamine decreased over the 48-hr period. Although the function of H 1 receptors on T cells, B cells, and monocytes has not been completely defined, this receptor has the potential of playing an important role in the modulating the immune response

  8. Interaction between G Protein-Coupled Receptor 143 and Tyrosinase: Implications for Understanding Ocular Albinism Type 1.

    De Filippo, Elisabetta; Schiedel, Anke C; Manga, Prashiela

    2017-02-01

    Developmental eye defects in X-linked ocular albinism type 1 are caused by G-protein coupled receptor 143 (GPR143) mutations. Mutations result in dysfunctional melanosome biogenesis and macromelanosome formation in pigment cells, including melanocytes and retinal pigment epithelium. GPR143, primarily expressed in pigment cells, localizes exclusively to endolysosomal and melanosomal membranes unlike most G protein-coupled receptors, which localize to the plasma membrane. There is some debate regarding GPR143 function and elucidating the role of this receptor may be instrumental for understanding neurogenesis during eye development and for devising therapies for ocular albinism type I. Many G protein-coupled receptors require association with other proteins to function. These G protein-coupled receptor-interacting proteins also facilitate fine-tuning of receptor activity and tissue specificity. We therefore investigated potential GPR143 interaction partners, with a focus on the melanogenic enzyme tyrosinase. GPR143 coimmunoprecipitated with tyrosinase, while confocal microscopy demonstrated colocalization of the proteins. Furthermore, tyrosinase localized to the plasma membrane when coexpressed with a GPR143 trafficking mutant. The physical interaction between the proteins was confirmed using fluorescence resonance energy transfer. This interaction may be required in order for GPR143 to function as a monitor of melanosome maturation. Identifying tyrosinase as a potential GPR143 binding protein opens new avenues for investigating the mechanisms that regulate pigmentation and neurogenesis. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  9. The angiotensin II type 2 receptor agonist Compound 21 is protective in experimental diabetes-associated atherosclerosis

    Chow, Bryna S M; Koulis, Christine; Krishnaswamy, Pooja

    2016-01-01

    AIMS/HYPOTHESIS: Angiotensin II is well-recognised to be a key mediator in driving the pathological events of diabetes-associated atherosclerosis via signalling through its angiotensin II type 1 receptor (AT1R) subtype. However, its actions via the angiotensin II type 2 receptor (AT2R) subtype...... are still poorly understood. This study is the first to investigate the role of the novel selective AT2R agonist, Compound 21 (C21) in an experimental model of diabetes-associated atherosclerosis (DAA). METHODS: Streptozotocin-induced diabetic Apoe-knockout mice were treated with vehicle (0.1 mol/l citrate...

  10. Type 1 cannabinoid receptor mapping with [18F]MK-9470 PET in the rat brain after quinolinic acid lesion: a comparison to dopamine receptors and glucose metabolism

    Casteels, Cindy; Martinez, Emili; Camon, Lluisa; Vera, Nuria de; Planas, Anna M.; Bormans, Guy; Baekelandt, Veerle; Laere, Koen van

    2010-01-01

    Several lines of evidence imply early alterations in metabolic, dopaminergic and endocannabinoid neurotransmission in Huntington's disease (HD). Using [ 18 F]MK-9470 and small animal PET, we investigated cerebral changes in type 1 cannabinoid (CB 1 ) receptor binding in the quinolinic acid (QA) rat model of HD in relation to glucose metabolism, dopamine D 2 receptor availability and amphetamine-induced turning behaviour. Twenty-one Wistar rats (11 QA and 10 shams) were investigated. Small animal PET acquisitions were conducted on a Focus 220 with approximately 18 MBq of [ 18 F]MK-9470, [ 18 F]FDG and [ 11 C]raclopride. Relative glucose metabolism and parametric CB 1 receptor and D 2 binding images were anatomically standardized to Paxinos space and analysed voxel-wise using Statistical Parametric Mapping (SPM2). In the QA model, [ 18 F]MK-9470 uptake, glucose metabolism and D 2 receptor binding were reduced in the ipsilateral caudate-putamen by 7, 35 and 77%, respectively (all p -5 ), while an increase for these markers was observed on the contralateral side (>5%, all p -4 ). [ 18 F]MK-9470 binding was also increased in the cerebellum (p = 2.10 -5 ), where it was inversely correlated to the number of ipsiversive turnings (p = 7.10 -6 ), suggesting that CB 1 receptor upregulation in the cerebellum is related to a better functional outcome. Additionally, glucose metabolism was relatively increased in the contralateral hippocampus, thalamus and sensorimotor cortex (p = 1.10 -6 ). These data point to in vivo changes in endocannabinoid transmission, specifically for CB 1 receptors in the QA model, with involvement of the caudate-putamen, but also distant regions of the motor circuitry, including the cerebellum. These data also indicate the occurrence of functional plasticity on metabolism, D 2 and CB 1 neurotransmission in the contralateral hemisphere. (orig.)

  11. receptores

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  12. Development and Effects of FTY720 Ophthalmic Solution on Corneal Allograft Survival

    Zhaochuan Liu; Haotian Lin; Chulong Huang; Wan Chen; Wu Xiang; Yu Geng; Weirong Chen

    2015-01-01

    Fingolimod (FTY720), a novel class of sphingosine 1-phosphate receptor modulators, has received special interest among ophthalmologists, particularly given that oral administration of FTY720 has proven to effectively treat corneal graft rejection in animal models. However, no studies have examined the performance of FTY720 as an ophthalmic solution in reducing corneal rejection in high-risk corneal rejection models, and the stability and ocular irritation profile of FTY720 ophthalmic solution...

  13. Prefrontal gamma-aminobutyric acid type A receptor insertion controls cue-induced relapse to nicotine seeking.

    Lubbers, Bart R; van Mourik, Yvar; Schetters, Dustin; Smit, August B; De Vries, Taco J; Spijker, Sabine

    2014-11-01

    Current smoking cessation therapies offer limited success, as relapse rates remain high. Nicotine, which is the major component of tobacco smoke, is thought to be primarily responsible for the addictive properties of tobacco. However, little is known about the molecular mechanisms underlying nicotine relapse, hampering development of more effective therapies. The objective of this study was to elucidate the role of medial prefrontal cortex (mPFC) glutamatergic and gamma-aminobutyric acid (GABA)ergic receptors in controlling relapse to nicotine seeking. Using an intravenous self-administration model, we studied glutamate and gamma-aminobutyric acid receptor regulation in the synaptic membrane fraction of the rat mPFC following extinction and cue-induced relapse to nicotine seeking. Subsequently, we locally intervened at the level of GABAergic signaling by using a mimetic peptide of the GABA receptor associated protein-interacting domain of GABA type A (GABAA) receptor subunit γ2 (TAT-GABAγ2) and muscimol, a GABAA receptor agonist. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and N-methyl-D-aspartate receptors were not regulated after the 30-min relapse test. However, GABAA receptor subunits α1 and γ2 were upregulated, and interference with GABAA receptor insertion in the cell membrane using the TAT-GABAγ2 peptide in the dorsal mPFC, but not the ventral mPFC, significantly increased responding during relapse. Increasing GABAA transmission with muscimol in the dorsal and ventral mPFC attenuated relapse. These data indicate that cue-induced relapse entails a GABAergic plasticity mechanism that limits nicotine seeking by restoring inhibitory control in the dorsal mPFC. GABAA receptor-mediated neurotransmission in the dorsal mPFC constitutes a possible future therapeutic target for maintaining smoking abstinence. Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  14. Dual specificity of activin type II receptor ActRIIb in dorso-ventral patterning during zebrafish embryogenesis.

    Nagaso, H; Suzuki, A; Tada, M; Ueno, N

    1999-04-01

    Members of the transforming growth factor-beta (TGF-beta) superfamily are thought to regulate specification of a variety of tissue types in early embryogenesis. These effects are mediated through a cell surface receptor complex, consisting of two classes of ser/thr kinase receptor, type I and type II. In the present study, cDNA encoding zebrafish activin type II receptors, ActRIIa and ActRIIb was cloned and characterized. Overexpression of ActRIIb in zebrafish embryos caused dorsalization of embryos, as observed in activin-overexpressing embryos. However, in blastula stage embryos, ActRIIb induced formation of both dorsal and ventro-lateral mesoderm. It has been suggested that these inducing signals from ActRIIb are mediated through each specific type I receptor, TARAM-A and BMPRIA, depending on activin and bone morphogenetic protein (BMP), respectively. In addition, it was shown that a kinase-deleted form of ActRIIb (dnActRIIb) suppressed both activin- and BMP-like signaling pathways. These results suggest that ActRIIb at least has dual roles in both activin and BMP signaling pathways during zebrafish embryogenesis.

  15. A case of pseudohypoaldosteronism type 1 with a mutation in the mineralocorticoid receptor gene

    Se Eun Lee

    2011-02-01

    Full Text Available Pseudohypoaldosteronism type 1 (PHA1 is a rare form of mineralocorticoid resistance characterized in newborns by salt wasting with dehydration, hyperkalemia and failure to thrive. This disease is heterogeneous in etiology and includes autosomal dominant PHA1 owing to mutations of the NR3C2 gene encoding the mineralocorticoid receptor, autosomal recessive PHA1 due to mutations of the epithelial sodium channel (ENaC gene, and secondary PHA1 associated with urinary tract diseases. Amongst these diseases, autosomal dominant PHA1 shows has manifestations restricted to renal tubules including a mild salt loss during infancy and that shows a gradual improvement with advancing age. Here, we report a neonatal case of PHA1 with a NR3C2 gene mutation (a heterozygous c.2146_2147insG in exon 5, in which the patient showed failure to thrive, hyponatremia, hyperkalemia, and elevated plasma renin and aldosterone levels. This is the first case of pseudohypoaldosteronism type 1 confirmed by genetic analysis in Korea.

  16. Chimeric Antigen Receptors in Different Cell Types: New Vehicles Join the Race.

    Harrer, Dennis C; Dörrie, Jan; Schaft, Niels

    2018-05-01

    Adoptive cellular therapy has evolved into a powerful force in the battle against cancer, holding promise for curative responses in patients with advanced and refractory tumors. Autologous T cells, reprogrammed to target malignant cells via the expression of a chimeric antigen receptor (CAR) represent the frontrunner in this approach. Tremendous clinical regressions have been achieved using CAR-T cells against a variety of cancers both in numerous preclinical studies and in several clinical trials, most notably against acute lymphoblastic leukemia, and resulted in a very recent United States Food and Drug Administration approval of the first CAR-T-cell therapy. In most studies CARs are transferred to conventional αβT cells. Nevertheless, transferring a CAR into different cell types, such as γδT cells, natural killer cells, natural killer T cells, and myeloid cells has yet received relatively little attention, although these cell types possess unique features that may aid in surmounting some of the hurdles CAR-T-cell therapy currently faces. This review focuses on CAR therapy using effectors beyond conventional αβT cells and discusses those strategies against the backdrop of developing a safe, powerful, and durable cancer therapy.

  17. Enhancement of GABAergic transmission by zolpidem, an imidazopyridine with preferential affinity for type I benzodiazepine receptors.

    Biggio, G; Concas, A; Corda, M G; Serra, M

    1989-02-28

    The effect of zolpidem, an imidazopyridine derivative with high affinity at the type I benzodiazepine recognition site, on the function of the GABAA/ionophore receptor complex was studied in vitro. Zolpidem, mimicking the action of diazepam, increased [3H]GABA binding, enhanced muscimol-stimulated 36Cl- uptake and reduced [35S]TBPS binding in rat cortical membrane preparations. Zolpidem was less effective than diazepam on the above parameters. Zolpidem induced a lower increase of [3H]GABA binding (23 vs. 35%) and muscimol-stimulated 36Cl- uptake (22 vs. 40%) and a smaller decrease of [35S]TBPS binding (47 vs. 77%) than diazepam. The finding that zolpidem enhanced the function of GABAergic synapses with an efficacy qualitatively and quantitatively different from that of diazepam suggests that this compound is a partial agonist at the benzodiazepine recognition site. Thus, our results are consistent with the view that the biochemical and pharmacological profile of a benzodiazepine recognition site ligand reflects its efficacy to enhance GABAergic transmission. Whether the preferential affinity of zolpidem at the type I site is involved in its atypical biochemical and pharmacological profile remains to be clarified.

  18. Receptor for advanced glycation end-products is a marker of type I lung alveolar cells.

    Shirasawa, Madoka; Fujiwara, Naoyuki; Hirabayashi, Susumu; Ohno, Hideki; Iida, Junko; Makita, Koshi; Hata, Yutaka

    2004-02-01

    Lung alveolar epithelial cells are comprised of type I (ATI) and type II (ATII) cells. ATI cells are polarized, although they have very flat morphology. The identification of marker proteins for apical and basolateral membranes of ATI cells is important to investigate into the differentiation of ATI cells. In this paper, we characterized receptor for advanced glycation end-products (RAGE) as a marker for ATI cells. RAGE was localized on basolateral membranes of ATI cells in the immunoelectron microscopy and its expression was enhanced in a parallel manner to the differentiation of ATI cells in vivo and in primary cultures of ATII cells. RAGE and T1 alpha, a well-known ATI marker protein, were targeted to basolateral and apical membranes, respectively, when expressed in polarized Madine Darby canine kidney cells. Moreover, RAGE was expressed in ATI cells after T1 alpha in vivo and in ex in vivo organ cultures. In conclusion, RAGE is a marker for basolateral membranes of well-differentiated ATI cells. ATI cells require some signal provided by the in vivo environment to express RAGE.

  19. Goat activin receptor type IIB knockdown by muscle specific promoter driven artificial microRNAs.

    Patel, Amrutlal K; Shah, Ravi K; Patel, Utsav A; Tripathi, Ajai K; Joshi, Chaitanya G

    2014-10-10

    Activin receptor type IIB (ACVR2B) is a transmembrane receptor which mediates signaling of TGF beta superfamily ligands known to function in regulation of muscle mass, embryonic development and reproduction. ACVR2B antagonism has shown to enhance the muscle growth in several disease and transgenic models. Here, we show ACVR2B knockdown by RNA interference using muscle creatine kinase (MCK) promoter driven artificial microRNAs (amiRNAs). Among the various promoter elements tested, the ∼1.26 kb MCK promoter region showed maximum transcriptional activity in goat myoblasts cells. We observed up to 20% silencing in non-myogenic 293T cells and up to 32% silencing in myogenic goat myoblasts by MCK directed amiRNAs by transient transfection. Goat myoblasts stably integrated with MCK directed amiRNAs showed merely 8% silencing in proliferating myoblasts which was increased to 34% upon induction of differentiation at transcript level whereas up to 57% silencing at protein level. Knockdown of ACVR2B by 5'-UTR derived amiRNAs resulted in decreased SMAD2/3 signaling, increased expression of myogenic regulatory factors (MRFs) and enhanced proliferation and differentiation of myoblasts. Unexpectedly, knockdown of ACVR2B by 3'-UTR derived amiRNAs resulted in increased SMAD2/3 signaling, reduced expression of MRFs and suppression of myogenesis. Our study offers muscle specific knockdown of ACVR2B as a potential strategy to enhance muscle mass in the farm animal species. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Autoantibodies against Muscarinic Type 3 Receptor in Sjögren's Syndrome Inhibit Aquaporin 5 Trafficking

    Lee, Byung Ha; Gauna, Adrienne E.; Perez, Geidys; Park, Yun-jong; Pauley, Kaleb M.; Kawai, Toshihisa; Cha, Seunghee

    2013-01-01

    Sjögren's syndrome (SjS) is a chronic autoimmune disease that mainly targets the salivary and lacrimal glands. It has been controversial whether anti-muscarinic type 3 receptor (α-M3R) autoantibodies in patients with SjS inhibit intracellular trafficking of aquaporin-5 (AQP5), water transport protein, leading to secretory dysfunction. To address this issue, GFP-tagged human AQP5 was overexpressed in human salivary gland cells (HSG-hAQP5) and monitored AQP5 trafficking to the plasma membrane following carbachol (CCh, M3R agonist) stimulation. AQP5 trafficking was indeed mediated by M3R stimulation, shown in partial blockage of trafficking by M3R-antagonist 4-DAMP. HSG-hAQP5 pre-incubated with SjS plasma for 24 hours significantly reduced AQP5 trafficking with CCh, compared with HSG-hAQP5 pre-incubated with healthy control (HC) plasma. This inhibition was confirmed by monoclonal α-M3R antibody and pre-absorbed plasma. Interestingly, HSG-hAQP5 pre-incubated with SjS plasma showed no change in cell volume, compared to the cells incubated with HC plasma showing shrinkage by twenty percent after CCh-stimulation. Our findings clearly indicate that binding of anti-M3R autoantibodies to the receptor, which was verified by immunoprecipitation, suppresses AQP5 trafficking to the membrane and contribute to impaired fluid secretion in SjS. Our current study urges further investigations of clinical associations between SjS symptoms, such as degree of secretory dysfunction, cognitive impairment, and/or bladder irritation, and different profiles (titers, isotypes, and/or specificity) of anti-M3R autoantibodies in individuals with SjS. PMID:23382834

  1. Pharmacological benefits of selective modulation of cannabinoid receptor type 2 (CB2) in experimental Alzheimer's disease.

    Jayant, Shalini; Sharma, Brij Mohan; Bansal, Rani; Sharma, Bhupesh

    2016-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disorder that pervasively affects the population across the world. Currently, there is no effective treatment available for this and existing drugs merely slow the progression of cognitive function decline. Thus, massive effort is required to find an intended therapeutic target to overcome this condition. The present study has been framed to investigate the ameliorative role of selective modulator of cannabinoid receptor type 2 (CB2), 1-phenylisatin in experimental AD condition. We have induced experimental AD in mice by using two induction models viz., intracerebroventricular (i.c.v.) administration of streptozotocin (STZ) and aluminum trichloride (AlCl3)+d-galactose. Morris water maze (MWM) and attentional set shifting test (ASST) were used to assess learning and memory. Hematoxylin-eosin and Congo red staining were used to examine the structural variation in brain. Brain oxidative stress (thiobarbituric acid reactive substance and glutathione), nitric oxide levels (nitrites/nitrates), acetyl cholinesterase activity, myeloperoxidase and calcium levels were also estimated. i.c.v. STZ as well as AlCl3+d-galactose have impaired spatial and reversal learning with executive functioning, increased brain oxidative and nitrosative stress, cholinergic activity, inflammation and calcium levels. Furthermore, these agents have also enhanced the burden of Aβ plaque in the brain. Treatment with 1-phenylisatin and donepezil attenuated i.c.v. STZ as well as AlCl3+d-galactose induced impairment of learning-memory, brain biochemistry and brain damage. Hence, this study concludes that CB2 receptor modulation can be a potential therapeutic target for the management of AD. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Generation and Characterization of Mice Expressing a Conditional Allele of the Interleukin-1 Receptor Type 1.

    Matthew J Robson

    Full Text Available The cytokines IL-1α and IL-1β exert powerful pro-inflammatory actions throughout the body, mediated primarily by the intracellular signaling capacity of the interleukin-1 receptor (IL-1R1. Although Il1r1 knockout mice have been informative with respect to a requirement for IL-1R1 signaling in inflammatory events, the constitutive nature of gene elimination has limited their utility in the assessment of temporal and spatial patterns of cytokine action. To pursue such questions, we have generated C57Bl/6J mice containing a floxed Il1r1 gene (Il1r1loxP/loxP, with loxP sites positioned to flank exons 3 and 4 and thereby the ability to spatially and temporally eliminate Il1r1 expression and signaling. We found that Il1r1loxP/loxP mice breed normally and exhibit no gross physical or behavioral phenotypes. Moreover, Il1r1loxP/loxP mice exhibit normal IL-1R1 receptor expression in brain and spleen, as well as normal IL-1R1-dependent increases in serum IL-6 following IL-1α injections. Breeding of Il1r1loxP/loxP mice to animals expressing a cytomegalovirus (CMV-driven Cre recombinase afforded efficient excision at the Il1r1 locus. The Il1r1loxP/loxP line should be a valuable tool for the assessment of contributions made by IL-1R1 signaling in diverse cell types across development.

  3. HIV type 1 chemokine receptor usage in mother-to-child transmission.

    Salvatori, F; Scarlatti, G

    2001-07-01

    To investigate the role of the HIV-1 phenotype in mother-to-child HIV-1 transmission, we evaluated coreceptor usage and replication kinetics in chemokine receptor-expressing U87MG.CD4 cells of primary isolates from 32 HIV-1-infected mothers of Italian origin, none under preventive antiretroviral therapy, and from their infected infants. Five of 15 mothers of infected children and 2 of 17 mothers of uninfected children harbored viruses able to use CXCR4 as coreceptor. However, all isolates used CCR5, alone or in association with CXCR4. The replicative capacity in coreceptor-expressing cells of the viral isolates did not differ between the two groups of mothers. All mothers with an R5 virus transmitted a virus with the same coreceptor usage, whereas those four with a multitropic virus transmitted such a virus in one case. Although the presence of a mixed viral population was documented in the mothers, we did not observe transmission solely of X4 viruses. Interestingly, the only child infected with a multitropic virus carried a defective CCR5 allele. Analysis of the env V3 region of the provirus from this child revealed infection with multiple viral variants with a predominance of R5-type over X4-type sequences. These findings show that CCR5 usage of a viral isolate is not a discriminating risk factor for vertical transmission. Furthermore, X4 viruses can be transmitted to the newborn, although less frequently. In particular, we document the transmission of multiple viral variants with different coreceptor usage in a Delta32 CCR5 heterozygous child, and demonstrate that the heterozygous genotype per se does not contribute to the restriction of R5-type virus spread.

  4. NF-kappaB signaling mediates vascular smooth muscle endothelin type B receptor expression in resistance arteries

    Zheng, Jian-Pu; Zhang, Yaping; Edvinsson, Lars

    2010-01-01

    Vascular smooth muscle cells (SMC) endothelin type B (ET(B)) receptor upregulation results in strong vasoconstriction and reduction of local blood flow. We hypothesizes that the underlying molecular mechanisms involve transcriptional factor nuclear factor-kappaB (NF-kappaB) pathway. ET(B) recepto...

  5. Increased migration of monocytes in essential hypertension is associated with increased transient receptor potential channel canonical type 3 channels

    Zhao, Zhigang; Ni, Yinxing; Chen, Jing

    2012-01-01

    Increased transient receptor potential canonical type 3 (TRPC3) channels have been observed in patients with essential hypertension. In the present study we tested the hypothesis that increased monocyte migration is associated with increased TRPC3 expression. Monocyte migration assay was performe...

  6. Cloning and characterization of SCART1, a novel scavenger receptor cysteine-rich type I transmembrane molecule

    Holm, Dorte; Fink, Dorte Rosenbek; Grønlund, Jørn

    2009-01-01

    We have cloned and characterized a novel murine transmembrane molecule, mSCART1 belonging to the scavenger receptor cysteine-rich superfamily. The cDNA encodes a polypeptide chain of 989 amino acids, organized as a type I transmembrane protein that contains eight extracellular SRCR domains followed...

  7. Quantitative PET of human urokinase-type plasminogen activator receptor with 64Cu-DOTA-AE105

    Persson, Morten; Madsen, Jacob; Østergaard, Søren

    2012-01-01

    Expression levels of the urokinase-type plasminogen activator receptor (uPAR) represent an established biomarker for poor prognosis in a variety of human cancers. The objective of the present study was to explore whether noninvasive PET can be used to perform a quantitative assessment of expressi...

  8. ANG II type 1 receptor antagonist irbesartan inhibits coronary angiogenesis stimulated by chronic intermittent hypoxia in neonatal rats

    Rakusan, K.; Chvojková, Zuzana; Oliviero, P.; Ošťádalová, Ivana; Kolář, František; Chassagne, C.; Samuel, J. L.; Ošťádal, Bohuslav

    2007-01-01

    Roč. 292, č. 3 (2007), H1237-H1244 ISSN 0363-6135 R&D Projects: GA MŠk 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : angiogenesis neonatal rat * ANG II type 1 receptor antagonist heart * ischemic tolerance Subject RIV: ED - Physiology Impact factor: 3.973, year: 2007

  9. Expression and Regulation of Corticotropin-Releasing Factor Receptor Type 2 beta in Developing and Mature Mouse Skeletal Muscle

    Kuperman, Yael; Issler, Orna; Vaughan, Joan; Bilezikjian, Louise; Vale, Wylie; Chen, Alon

    Corticotropin-releasing factor receptor type 2 (CRFR2) is highly expressed in skeletal muscle (SM) tissue where it is suggested to inhibit interactions between insulin signaling pathway components affecting whole-body glucose homeostasis. However, little is known about factors regulating SM CRFR2

  10. Regulation of Mg2+ Reabsorption and Transient Receptor Potential Melastatin Type 6 Activity by cAMP Signaling.

    Blanchard, M.G.; Kittikulsuth, W.; Nair, A.V.; Baaij, J.H.F. de; Latta, F.; Genzen, J.R.; Kohan, D.E.; Bindels, R.J.M.; Hoenderop, J.G.J.

    2016-01-01

    The transient receptor potential melastatin type 6 (TRPM6) epithelial Mg(2+) channels participate in transcellular Mg(2+) transport in the kidney and intestine. Previous reports suggested a hormonal cAMP-dependent regulation of Mg(2+) reabsorption in the kidney. The molecular details of this process

  11. Glycoprotein 130 receptor signaling mediates α-cell dysfunction in a rodent model of type 2 diabetes

    Chow, Samuel Z; Speck, Madeleine; Yoganathan, Piriya

    2014-01-01

    Dysregulated glucagon secretion accompanies islet inflammation in type 2 diabetes. We recently discovered that interleukin (IL)-6 stimulates glucagon secretion from human and rodent islets. IL-6 family cytokines require the glycoprotein 130 (gp130) receptor to signal. In this study, we elucidated...

  12. Estrogen receptor-independent catechol estrogen binding activity: protein binding studies in wild-type, Estrogen receptor-alpha KO, and aromatase KO mice tissues.

    Philips, Brian J; Ansell, Pete J; Newton, Leslie G; Harada, Nobuhiro; Honda, Shin-Ichiro; Ganjam, Venkataseshu K; Rottinghaus, George E; Welshons, Wade V; Lubahn, Dennis B

    2004-06-01

    Primary evidence for novel estrogen signaling pathways is based upon well-documented estrogenic responses not inhibited by estrogen receptor antagonists. In addition to 17beta-E2, the catechol estrogen 4-hydroxyestradiol (4OHE2) has been shown to elicit biological responses independent of classical estrogen receptors in estrogen receptor-alpha knockout (ERalphaKO) mice. Consequently, our research was designed to biochemically characterize the protein(s) that could be mediating the biological effects of catechol estrogens using enzymatically synthesized, radiolabeled 4-hydroxyestrone (4OHE1) and 4OHE2. Scatchard analyses identified a single class of high-affinity (K(d) approximately 1.6 nM), saturable cytosolic binding sites in several ERalphaKO estrogen-responsive tissues. Specific catechol estrogen binding was competitively inhibited by unlabeled catechol estrogens, but not by 17beta-E2 or the estrogen receptor antagonist ICI 182,780. Tissue distribution studies indicated significant binding differences both within and among various tissues in wild-type, ERalphaKO, and aromatase knockout female mice. Ligand metabolism experiments revealed extensive metabolism of labeled catechol estrogen, suggesting that catechol estrogen metabolites were responsible for the specific binding. Collectively, our data provide compelling evidence for the interaction of catechol estrogen metabolites with a novel binding protein that exhibits high affinity, specificity, and selective tissue distribution. The extensive biochemical characterization of this binding protein indicates that this protein may be a receptor, and thus may mediate ERalpha/beta-independent effects of catechol estrogens and their metabolites.

  13. Inhibitory effects of azole-type fungicides on interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

    Kojima, Hiroyuki; Muromoto, Ryuta; Takahashi, Miki; Takeuchi, Shinji; Takeda, Yukimasa; Jetten, Anton M.; Matsuda, Tadashi

    2013-01-01

    The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. However, it remains unclear whether environmental chemicals, including pesticides, have agonistic and/or antagonistic activity against RORα/γ. In this study, we investigated the RORα/γ activity of several azole-type fungicides, and the effects of these fungicides on the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In the ROR-reporter gene assays, five azole-type fungicides (imibenconazole, triflumizole, hexaconazole, tetraconazole and imazalil) suppressed RORα- and/or RORγ-mediated transcriptional activity as did benzenesulphonamide T0901317, a ROR inverse agonist and a liver X receptor (LXR) agonist. In particular, imibenconazole, triflumizole and hexaconazole showed RORγ inverse agonistic activity at concentrations of 10−6 M. However, unlike T0901317, these fungicides failed to show any LXRα/β agonistic activity. Next, five azole-type fungicides, showing ROR inverse agonist activity, were tested on IL-17 mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin. The quantitative RT-PCR analysis revealed that these fungicides suppressed the expression of IL-17 mRNA without effecting RORα and RORγ mRNA levels. In addition, the inhibitory effect of imibenconazole as well as that of T0901317 was absorbed in RORα/γ-knocked down EL4 cells. Taken together, these results suggest that some azole-type fungicides inhibit IL-17 production via RORα/γ. This also provides the first evidence that environmental chemicals can act as modulators of IL-17 expression in immune cells. PMID:22289359

  14. Bile salt receptor complex activates a pathogenic type III secretion system

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N; Salomon, Dor; Tomchick, Diana R; Grishin, Nick V; Orth, Kim

    2016-01-01

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered that Vibrio parahaemolyticus VtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment. DOI: http://dx.doi.org/10.7554/eLife.15718.001 PMID:27377244

  15. Bile salt receptor complex activates a pathogenic type III secretion system

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N.; Salomon, Dor; Tomchick, Diana R.; Grishin, Nick V.; Orth, Kim

    2016-07-05

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered thatVibrio parahaemolyticusVtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment.

  16. Nitric oxide-induced calcium release: activation of type 1 ryanodine receptor by endogenous nitric oxide.

    Kakizawa, Sho; Yamazawa, Toshiko; Iino, Masamitsu

    2013-01-01

    Ryanodine receptors (RyRs), located in the sarcoplasmic/endoplasmic reticulum (SR/ER) membrane, are required for intracellular Ca2+ release that is involved in a wide range of cellular functions. In addition to Ca2+-induced Ca2+ release in cardiac cells and voltage-induced Ca2+ release in skeletal muscle cells, we recently identified another mode of intracellular Ca2+ mobilization mediated by RyR, i.e., nitric oxide-induced Ca2+ release (NICR), in cerebellar Purkinje cells. NICR is evoked by neuronal activity, is dependent on S-nitrosylation of type 1 RyR (RyR1) and is involved in the induction of long-term potentiation (LTP) of cerebellar synapses. In this addendum, we examined whether peroxynitrite, which is produced by the reaction of nitric oxide with superoxide, may also have an effect on the Ca2+ release via RyR1 and the cerebellar LTP. We found that scavengers of peroxynitrite have no significant effect either on the Ca2+ release via RyR1 or on the cerebellar LTP. We also found that an application of a high concentration of peroxynitrite does not reproduce neuronal activity-dependent Ca2+ release in Purkinje cells. These results support that NICR is induced by endogenous nitric oxide produced by neuronal activity through S-nitrosylation of RyR1.

  17. Leukemia inhibitory factor promote trophoblast invasion via urokinase-type plasminogen activator receptor in preeclampsia.

    Zheng, Qin; Dai, Kuixing; Cui, Xinyuan; Yu, Ming; Yang, Xuesong; Yan, Bin; Liu, Shuai; Yan, Qiu

    2016-05-01

    Preeclampsia is a pregnancy-related syndrome which can cause perinatal mortality and morbidity. Inadequate invasion by trophoblast cells may lead to poor perfusion of the placenta, even result in preeclampsia. Understanding the molecular mechanisms underlying placentation facilitates the better intervention of preeclampsia. Urokinase-type plasminogen activator receptor (uPAR) is involved in the physiological and pathological processes. Leukemia inhibitory factor (LIF) is an important regulator in the establishment of pregnancy. However, the expression of uPAR in preeclamptic patients and its relationship with LIF remains unclear. In the current study, we found that the level of uPAR was relatively lower in the placentas from preeclamptic patients as compared with normal pregnant women. LIF promoted trophoblast cell outgrowth by upregulating uPAR in an explants culture, and LIF also enhanced migration and invasion potential through uPAR in trophoblast JAR and JEG-3 cell lines, and with increased gelatinolytic activities of matrix metalloproteinase 2 (MMP-2). The effect of LIF and uPAR on trophoblast migration and invasion was mediated by PI3K/AKT signaling pathway. Our data indicates the roles of LIF in promoting trophoblast migration and invasion through uPAR and suggest that abnormal expression of uPAR might be associated with the etiology of preeclampsia. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Intermolecular failure of L-type Ca2+ channel and ryanodine receptor signaling in hypertrophy.

    Ming Xu

    2007-02-01

    Full Text Available Pressure overload-induced hypertrophy is a key step leading to heart failure. The Ca(2+-induced Ca(2+ release (CICR process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca(2+ channel (LCC and ryanodine receptors (RyRs in aortic stenosis rat models of compensated (CHT and decompensated (DHT hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of "intermolecular failure." Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca(2+ release, visualized as "Ca(2+ spikes," became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca(2+ transients in CHT. These data suggested that, within a certain limit, termed the "stability margin," mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of "hidden" intermolecular failure in CHT has important clinical implications.

  19. Angiotensin II type 1 receptor blockers increase tolerance of cells to copper and cisplatin

    Pieter Spincemaille

    2014-10-01

    Full Text Available The human pathology Wilson disease (WD is characterized by toxic copper (Cu accumulation in brain and liver, resulting in, among other indications, mitochondrial dysfunction and apoptosis of hepatocytes. In an effort to identify novel compounds that can alleviate Cu-induced toxicity, we screened the Pharmakon 1600 repositioning library using a Cu-toxicity yeast screen. We identified 2 members of the drug class of Angiotensin II Type 1 receptor blockers (ARBs that could increase yeast tolerance to Cu, namely Candesartan and Losartan. Subsequently, we show that specific ARBs can increase yeast tolerance to Cu and/or the chemotherapeutic agent cisplatin (Cp. The latter also induces mitochondrial dysfunction and apoptosis in mammalian cells. We further demonstrate that specific ARBs can prevent the prevalence of Cu-induced apoptotic markers in yeast, with Candesartan Cilexetil being the ARB which demonstrated most pronounced reduction of apoptosis-related markers. Next, we tested the sensitivity of a selection of yeast knockout mutants affected in detoxification of reactive oxygen species (ROS and Cu for Candesartan Cilexetil rescue in presence of Cu. These data indicate that Candesartan Cilexetil increases yeast tolerance to Cu irrespectively of major ROS-detoxifying proteins. Finally, we show that specific ARBs can increase mammalian cell tolerance to Cu, as well as decrease the prevalence of Cu-induced apoptotic markers. All the above point to the potential of ARBs in preventing Cu-induced toxicity in yeast and mammalian cells.

  20. Coupling of SK channels, L-type Ca2+ channels, and ryanodine receptors in cardiomyocytes.

    Zhang, Xiao-Dong; Coulibaly, Zana A; Chen, Wei Chun; Ledford, Hannah A; Lee, Jeong Han; Sirish, Padmini; Dai, Gu; Jian, Zhong; Chuang, Frank; Brust-Mascher, Ingrid; Yamoah, Ebenezer N; Chen-Izu, Ye; Izu, Leighton T; Chiamvimonvat, Nipavan

    2018-03-16

    Small-conductance Ca 2+ -activated K + (SK) channels regulate the excitability of cardiomyocytes by integrating intracellular Ca 2+ and membrane potentials on a beat-to-beat basis. The inextricable interplay between activation of SK channels and Ca 2+ dynamics suggests the pathology of one begets another. Yet, the exact mechanistic underpinning for the activation of cardiac SK channels remains unaddressed. Here, we investigated the intracellular Ca 2+ microdomains necessary for SK channel activation. SK currents coupled with Ca 2+ influx via L-type Ca 2+ channels (LTCCs) continued to be elicited after application of caffeine, ryanodine or thapsigargin to deplete SR Ca 2+ store, suggesting that LTCCs provide the immediate Ca 2+ microdomain for the activation of SK channels in cardiomyocytes. Super-resolution imaging of SK2, Ca v 1.2 Ca 2+ channel, and ryanodine receptor 2 (RyR2) was performed to quantify the nearest neighbor distances (NND) and localized the three molecules within hundreds of nanometers. The distribution of NND between SK2 and RyR2 as well as SK2 and Ca v 1.2 was bimodal, suggesting a spatial relationship between the channels. The activation mechanism revealed by our study paved the way for the understanding of the roles of SK channels on the feedback mechanism to regulate the activities of LTCCs and RyR2 to influence local and global Ca 2+ signaling.

  1. Type 1 IGF Receptor Localization in Paediatric Gliomas: Significant Association with WHO Grading and Clinical Outcome.

    Clément, Florencia; Martin, Ayelen; Venara, Marcela; de Luján Calcagno, Maria; Mathó, Cecilia; Maglio, Silvana; Lombardi, Mercedes García; Bergadá, Ignacio; Pennisi, Patricia A

    2018-06-01

    Nuclear localization of insulin-like growth factor receptor type 1 (IGF-1R) has been described as adverse prognostic factor in some cancers. We studied the expression and localization of IGF-1R in paediatric patients with gliomas, as well as its association with World Health Organization (WHO) grading and survival. We conducted a single cohort, prospective study of paediatric patients with gliomas. Samples were taken at the time of the initial surgery; IGF-1R expression and localization were characterized by immunohistochemistry (IHC), subcellular fractionation and western blotting. Tumours (47/53) showed positive staining for IGF-1R by IHC. IGF-1R nuclear labelling was observed in 10/47 cases. IGF-1R staining was mostly non-nuclear in low-grade tumours, while IGF-1R nuclear labelling was predominant in high-grade gliomas (p = 0.0001). Survival was significantly longer in patients with gliomas having non-nuclear IGF-1R localization than in patients with nuclear IGF-1R tumours (p = 0.016). In gliomas, IGF-1R nuclear localization was significantly associated with both high-grade tumours and increased risk of death. Based on a prospective design, we provide evidence of a potential usefulness of intracellular localization of IGF-1R as prognostic factor in paediatric patients with gliomas.

  2. Angiotensin II type 1 receptor (A1166C gene polymorphism and essential hypertension in Egyptian population

    Marium M. Shamaa

    2016-09-01

    Full Text Available The pathogenesis of essential hypertension (EH is affected by genetic and environmental factors. Mutations in hypertension-related genes can affect blood pressure (BP via alteration of salt and water reabsorption by the nephron. The genes of the renin-angiotensin system (RAS have been extensively studied because of the well documented role of this system in the control of BP. It has been previously shown that Angiotensin II type 1 receptor (ATR1 gene polymorphism could be associated with increased risk of EH. So, in the current study, we evaluated the frequency of ATR1 (A1166C polymorphism in relation to EH in a group of Egyptian population. The study population included 83 hypertensive patients and 60 age and sex matched healthy control subjects. Restriction fragment length polymorphism – Polymerase chain reaction (RFLP – PCR was used for the analysis of A1166C polymorphism of ATR1 genes in peripheral blood samples of all patients and controls. The results revealed that there was a positive risk of developing EH when having the T allele whether in homozygous or heterozygous state. From this work, it was concluded that there was an association between ATR1 (A1166C gene polymorphism and the risk of developing EH.

  3. SP600125 Induces Src and Type I IGF Receptor Phosphorylation Independent of JNK

    Qingbin Kong

    2014-09-01

    Full Text Available c-Jun N-terminal kinases (JNK are members of the mitogen-activated protein kinase (MAPK family that have important roles in signal transduction. The small molecule SP600125 is widely used in biochemical studies as a JNK inhibitor. However, recent studies indicate that SP600125 may also act independent of JNK. Here, we report that SP600125 can induce Src, type I insulin-like growth factor receptor (IGF-IR, Akt and Erk1/2 phosphorylation. Notably, these effects are independent of its inhibition of JNK. Inhibition of Src abrogates the stimulation of IGF-IR, Akt and Erk1/2 phosphorylation. IGF-IR knockdown blunts the induction of both Akt and Erk1/2 phosphorylation by SP600125. Moreover, combination of SP600125 and the Src inhibitor saracatinib synergistically inhibits cell proliferation. We conclude that SP600125 can activate Src-IGF-IR-Akt/Erk1/2 signaling pathways independent of JNK.

  4. Beyond T and DHT - novel steroid derivatives capable of wild type androgen receptor activation.

    Mostaghel, Elahe A

    2014-01-01

    While androgen deprivation therapy (ADT) remains the primary treatment for metastatic prostate cancer (PCa), castration does not eliminate androgens from the prostate tumor microenvironment, and residual intratumoral androgens are implicated in nearly every mechanism by which androgen receptor (AR)-mediated signaling promotes castration-resistant disease. The uptake and intratumoral (intracrine) conversion of circulating adrenal androgens such as dehydroepiandrosterone sulfate (DHEA-S) to steroids capable of activating the wild type AR is a recognized driver of castration resistant prostate cancer (CRPC). However, less well-characterized adrenal steroids, including 11-deoxcorticosterone (DOC) and 11beta-hydroxyandrostenedione (11OH-AED) may also play a previously unrecognized role in promoting AR activation. In particular, recent data demonstrate that the 5α-reduced metabolites of DOC and 11OH-AED are activators of the wild type AR. Given the well-recognized presence of SRD5A activity in CRPC tissue, these observations suggest that in the low androgen environment of CRPC, alternative sources of 5α-reduced ligands may supplement AR activation normally mediated by the canonical 5α-reduced agonist, 5α-DHT. Herein we review the emerging data that suggests a role for these alternative steroids of adrenal origin in activating the AR, and discuss the enzymatic pathways and novel downstream metabolites mediating these effects. We conclude by discussing the potential implications of these findings for CRPC progression, particularly in context of new agents such as abiraterone and enzalutamide which target the AR-axis for prostate cancer therapy.

  5. Aberrant methylation of the M-type phospholipase A2 receptor gene in leukemic cells

    Menschikowski, Mario; Platzbecker, Uwe; Hagelgans, Albert; Vogel, Margot; Thiede, Christian; Schönefeldt, Claudia; Lehnert, Renate; Eisenhofer, Graeme; Siegert, Gabriele

    2012-01-01

    The M-type phospholipase A2 receptor (PLA2R1) plays a crucial role in several signaling pathways and may act as tumor-suppressor. This study examined the expression and methylation of the PLA2R1 gene in Jurkat and U937 leukemic cell lines and its methylation in patients with myelodysplastic syndrome (MDS) or acute leukemia. Sites of methylation of the PLA2R1 locus were identified by sequencing bisulfite-modified DNA fragments. Methylation specific-high resolution melting (MS-HRM) analysis was then carried out to quantify PLA2R1 methylation at 5-CpG sites identified with differences in methylation between healthy control subjects and leukemic patients using sequencing of bisulfite-modified genomic DNA. Expression of PLA2R1 was found to be completely down-regulated in Jurkat and U937 cells, accompanied by complete methylation of PLA2R1 promoter and down-stream regions; PLA2R1 was re-expressed after exposure of cells to 5-aza-2´-deoxycytidine. MS-HRM analysis of the PLA2R1 locus in patients with different types of leukemia indicated an average methylation of 28.9% ± 17.8%, compared to less than 9% in control subjects. In MDS patients the extent of PLA2R1 methylation significantly increased with disease risk. Furthermore, measurements of PLA2R1 methylation appeared useful for predicting responsiveness to the methyltransferase inhibitor, azacitidine, as a pre-emptive treatment to avoid hematological relapse in patients with high-risk MDS or acute myeloid leukemia. The study shows for the first time that PLA2R1 gene sequences are a target of hypermethylation in leukemia, which may have pathophysiological relevance for disease evolution in MDS and leukemogenesis

  6. Type I interferon and pattern recognition receptor signaling following particulate matter inhalation

    Erdely Aaron

    2012-07-01

    Full Text Available Abstract Background Welding, a process that generates an aerosol containing gases and metal-rich particulates, induces adverse physiological effects including inflammation, immunosuppression and cardiovascular dysfunction. This study utilized microarray technology and subsequent pathway analysis as an exploratory search for markers/mechanisms of in vivo systemic effects following inhalation. Mice were exposed by inhalation to gas metal arc – stainless steel (GMA-SS welding fume at 40 mg/m3 for 3 hr/d for 10 d and sacrificed 4 hr, 14 d and 28 d post-exposure. Whole blood cells, aorta and lung were harvested for global gene expression analysis with subsequent Ingenuity Pathway Analysis and confirmatory qRT-PCR. Serum was collected for protein profiling. Results The novel finding was a dominant type I interferon signaling network with the transcription factor Irf7 as a central component maintained through 28 d. Remarkably, these effects showed consistency across all tissues indicating a systemic type I interferon response that was complemented by changes in serum proteins (decreased MMP-9, CRP and increased VCAM1, oncostatin M, IP-10. In addition, pulmonary expression of interferon α and β and Irf7 specific pattern recognition receptors (PRR and signaling molecules (Ddx58, Ifih1, Dhx58, ISGF3 were induced, an effect that showed specificity when compared to other inflammatory exposures. Also, a canonical pathway indicated a coordinated response of multiple PRR and associated signaling molecules (Tlr7, Tlr2, Clec7a, Nlrp3, Myd88 to inhalation of GMA-SS. Conclusion This methodological approach has the potential to identify consistent, prominent and/or novel pathways and provides insight into mechanisms that contribute to pulmonary and systemic effects following toxicant exposure.

  7. Up-Regulation of Endothelin Type A Receptor in Human and Rat Radiation Proctitis: Preclinical Therapeutic Approach With Endothelin Receptor Blockade

    Jullien, Nicolash; Blirando, Karl; Milliat, Fabien; Sabourin, Jean-Christophe; Benderitter, Marc; Francois, Agnes

    2009-01-01

    Purpose: Rectum radiation damage and fibrosis are often associated with radiation therapy of pelvic tumors. The endothelin (ET) system has been implicated in several fibrotic diseases but never studied in the context of gastrointestinal radiation damage. This study assessed modifications in ET type 1 (ET-1), ET type A receptor (ET A ), and ET type B receptor (ET B ) localization and/or expression in irradiated human rectal tissue and in a rat model of delayed colorectal injury. We also evaluated the therapeutic potential of long-term ET receptor blockade. Methods and Materials: Routine histological studies of sections of healthy and radiation-injured human rectum tissue were done; the sections were also immunostained for ET A and ET B receptors. The rat model involved the delivery of 27 Gy in a single dose to the colons and rectums of the animals. The ET-1/ET A /ET B expression and ET A /ET B localization were studied at 10 weeks postexposure. The abilities of bosentan and atrasentan to protect against delayed rectal injury were also investigated. Results: The immunolocalization of ET A and ET B in healthy human rectums was similar to that in rat rectums. However, strong ET A immunostaining was seen in the presence of human radiation proctitis, and increased ET A mRNA levels were seen in the rat following colorectal irradiation. Immunostaining for ET A was also strongly positive in rats in areas of radiation-induced mucosal ulceration, atypia, and fibroproliferation. However, neither bosentan nor atrasentan prevented radiation damage to the rectum when given long term. The only effect seen for atrasentan was an increased number of sclerotic vessel sections in injured tissues. Conclusions: As the result of the overexpression of ET A , radiation exposure deregulates the endothelin system through an 'ET A profile' in the human and rodent rectum. However, therapeutic interventions involving mixed or specific ET A receptor blockade do not prevent radiation damage

  8. Inhibitory effects of azole-type fungicides on interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

    Kojima, Hiroyuki, E-mail: kojima@iph.pref.hokkaido.jp [Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo 060-0819 (Japan); Muromoto, Ryuta; Takahashi, Miki [Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812 (Japan); Takeuchi, Shinji [Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo 060-0819 (Japan); Takeda, Yukimasa; Jetten, Anton M. [National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709 (United States); Matsuda, Tadashi [Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812 (Japan)

    2012-03-15

    The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. However, it remains unclear whether environmental chemicals, including pesticides, have agonistic and/or antagonistic activity against RORα/γ. In this study, we investigated the RORα/γ activity of several azole-type fungicides, and the effects of these fungicides on the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In the ROR-reporter gene assays, five azole-type fungicides (imibenconazole, triflumizole, hexaconazole, tetraconazole and imazalil) suppressed RORα- and/or RORγ-mediated transcriptional activity as did benzenesulphonamide T0901317, a ROR inverse agonist and a liver X receptor (LXR) agonist. In particular, imibenconazole, triflumizole and hexaconazole showed RORγ inverse agonistic activity at concentrations of 10{sup −6} M. However, unlike T0901317, these fungicides failed to show any LXRα/β agonistic activity. Next, five azole-type fungicides, showing ROR inverse agonist activity, were tested on IL-17 mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin. The quantitative RT-PCR analysis revealed that these fungicides suppressed the expression of IL-17 mRNA without effecting RORα and RORγ mRNA levels. In addition, the inhibitory effect of imibenconazole as well as that of T0901317 was absorbed in RORα/γ-knocked down EL4 cells. Taken together, these results suggest that some azole-type fungicides inhibit IL-17 production via RORα/γ. This also provides the first evidence that environmental chemicals can act as modulators of IL-17 expression in immune cells. -- Highlights: ► Nuclear receptors, RORα and RORγ, are key regulators of Th17 cell differentiation. ► Five azole-type fungicides act as RORα/γ inverse agonists. ► These fungicides

  9. Inhibitory effects of azole-type fungicides on interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

    Kojima, Hiroyuki; Muromoto, Ryuta; Takahashi, Miki; Takeuchi, Shinji; Takeda, Yukimasa; Jetten, Anton M.; Matsuda, Tadashi

    2012-01-01

    The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. However, it remains unclear whether environmental chemicals, including pesticides, have agonistic and/or antagonistic activity against RORα/γ. In this study, we investigated the RORα/γ activity of several azole-type fungicides, and the effects of these fungicides on the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In the ROR-reporter gene assays, five azole-type fungicides (imibenconazole, triflumizole, hexaconazole, tetraconazole and imazalil) suppressed RORα- and/or RORγ-mediated transcriptional activity as did benzenesulphonamide T0901317, a ROR inverse agonist and a liver X receptor (LXR) agonist. In particular, imibenconazole, triflumizole and hexaconazole showed RORγ inverse agonistic activity at concentrations of 10 −6 M. However, unlike T0901317, these fungicides failed to show any LXRα/β agonistic activity. Next, five azole-type fungicides, showing ROR inverse agonist activity, were tested on IL-17 mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin. The quantitative RT-PCR analysis revealed that these fungicides suppressed the expression of IL-17 mRNA without effecting RORα and RORγ mRNA levels. In addition, the inhibitory effect of imibenconazole as well as that of T0901317 was absorbed in RORα/γ-knocked down EL4 cells. Taken together, these results suggest that some azole-type fungicides inhibit IL-17 production via RORα/γ. This also provides the first evidence that environmental chemicals can act as modulators of IL-17 expression in immune cells. -- Highlights: ► Nuclear receptors, RORα and RORγ, are key regulators of Th17 cell differentiation. ► Five azole-type fungicides act as RORα/γ inverse agonists. ► These fungicides suppress

  10. MCL and mincle: C-type lectin receptors that sense damaged self and pathogen associated molecular patterns

    Mark B Richardson

    2014-06-01

    Full Text Available MCL (macrophage C-type lectin and mincle (macrophage inducible C-type lectin comprise part of an extensive repertoire of pattern recognition receptors with the ability to sense damage associated and pathogen associated molecular patterns. In this review we cover the discovery and molecular characterization of these C-type lectin receptors, and highlight recent advances in the understanding of their roles in orchestrating the response of the immune system to bacterial and fungal infection, and damaged self. We also discuss the identification and structure-activity relationships of activating ligands, particularly trehalose dimycolate (TDM and related mycobacterial glycolipids, which have significant potential in the development of TH1/TH17 vaccination strategies.

  11. Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor

    Nørgaard, P; Damstrup, L; Rygaard, K

    1994-01-01

    was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating...

  12. Insulin-like growth factor type-1 receptor down-regulation associated with dwarfism in Holstein calves.

    Blum, J W; Elsasser, T H; Greger, D L; Wittenberg, S; de Vries, F; Distl, O

    2007-10-01

    Perturbations in endocrine functions can impact normal growth. Endocrine traits were studied in three dwarf calves exhibiting retarded but proportionate growth and four phenotypically normal half-siblings, sired by the same bull, and four unrelated control calves. Plasma 3,5,3'-triiodothyronine and thyroxine concentrations in dwarfs and half-siblings were in the physiological range and responded normally to injected thyroid-releasing hormone. Plasma glucagon concentrations were different (dwarfs, controls>half-siblings; Pcontrols, Pcontrols, P=0.08). Responses of GH to xylazine and to a GH-releasing-factor analogue were similar in dwarfs and half-siblings. Relative gene expression of IGF-1, IGF-2, GH receptor (GHR), insulin receptor, IGF-1 type-1 and -2