The Experts below are selected from a list of 306096 Experts worldwide ranked by ideXlab platform
Timothy Hla - One of the best experts on this subject based on the ideXlab platform.
-
signaling of sphingosine 1 phosphate via the s1p edg family of g protein coupled receptors
Biochimica et Biophysica Acta, 2002Co-Authors: Michael J Kluk, Timothy HlaAbstract:The sphingosine-1-phosphate/Endothelial Differentiation Gene (S1P/EDG) family of G-protein-coupled receptors (GPCR) currently includes five different isoforms, which differentially regulate fundamental cellular processes such as migration, proliferation, cytoskeletal organization, adherens junction assembly and morphoGenesis. Additionally, specific S1P/EDG isoforms can regulate important physiological processes such as blood vessel maturation, cardiac development and angioGenesis in vivo. Herein, we review the current state of knowledge of the expression patterns, signaling pathways and functional characteristics of the different S1P receptors. Further investigation in this field will likely improve our understanding of cardiovascular development as well as vascular diseases and may lead to novel therapeutic approaches.
-
sphingosine 1 phosphate activates akt nitric oxide production and chemotaxis through a gi protein phosphoinositide 3 kinase pathway in endothelial cells
Journal of Biological Chemistry, 2001Co-Authors: Manuel Moralesruiz, Menq Jer Lee, Timothy Hla, Stefan Zollner, Jeanphilippe Gratton, Ramona S Scotland, Ichiro Shiojima, Kenneth Walsh, William C SessaAbstract:Sphingosine 1-phosphate (SPP) binds to members of the endothelial Differentiation Gene family (EDG) of receptors and leads to diverse signaling events including cell survival, growth, migration and Differentiation. However, the mechanisms of how SPP activates these proangiogenic pathways are poorly understood. Here we show that SPP signals through the EDG-1 receptor to the heterotrimeric G protein Gi, leading to activation of the serine/threonine kinase Akt and phosphorylation of the Akt substrate, endothelial nitric-oxide synthase (eNOS). Inhibition of Gisignaling, and phosphoinositide 3-kinase (PI 3-kinase) activity resulted in a decrease in SPP-induced endothelial cell chemotaxis. SPP also stimulates eNOS phosphorylation and NO release and these effects are also attenuated by inhibition of Gi signaling, PI 3-kinase, and Akt. However, inhibition of NO production did not influence SPP-induced chemotaxis but effectively blocked the chemotactic actions of vascular endothelial growth factor. Thus, SPP signals through Gi and PI 3-kinase leading to Akt activation and eNOS phosphorylation.
-
sphingosine 1 phosphate induced endothelial cell migration requires the expression of edg 1 and edg 3 receptors and rho dependent activation of αvβ3 and β1 containing integrins
Journal of Biological Chemistry, 2001Co-Authors: Ji H Paik, Sung Suk Chae, Menq Jer Lee, Shobha Thangada, Timothy HlaAbstract:Sphingosine 1-phosphate (SPP), a platelet-derived bioactive lysophospholipid, is a regulator of angioGenesis. However, molecular mechanisms involved in SPP-induced angiogenic responses are not fully defined. Here we report the molecular mechanisms involved in SPP-induced human umbilical vein endothelial cell (HUVEC) adhesion and migration. SPP-induced HUVEC migration is potently inhibited by antisense phosphothioate oligonucleotides against EDG-1 as well as EDG-3 receptors. In addition, C3 exotoxin blocked SPP-induced cell attachment, spreading and migration on fibronectin-, vitronectin- and Matrigel-coated surfaces, suggesting that endothelial Differentiation Gene receptor signaling via the Rho pathway is critical for SPP-induced cell migration. Indeed, SPP induced Rho activation in an adherence-independent manner, whereas Rac activation was dispensible for cell attachment and focal contact formation. Interestingly, both EDG-1 and -3 receptors were required for Rho activation. Since integrins are critical for cell adhesion, migration, and angioGenesis, we examined the effects of blocking antibodies against alpha(v)beta(3), beta(1), or beta(3) integrins. SPP induced Rho-dependent integrin clustering into focal contact sites, which was essential for cell adhesion, spreading and migration. Blockage of alpha(v)beta(3)- or beta(1)-containing integrins inhibited SPP-induced HUVEC migration. Together our results suggest that endothelial Differentiation Gene receptor-mediated Rho signaling is required for the activation of integrin alpha(v)beta(3) as well as beta(1)-containing integrins, leading to the formation of initial focal contacts and endothelial cell migration.
-
sphingosine 1 phosphate induced endothelial cell migration requires the expression of edg 1 and edg 3 receptors and rho dependent activation of αvβ3 and β1 containing integrins
Journal of Biological Chemistry, 2001Co-Authors: Ji H Paik, Sung Suk Chae, Menq Jer Lee, Shobha Thangada, Timothy HlaAbstract:Sphingosine 1-phosphate (SPP), a platelet-derived bioactive lysophospholipid, is a regulator of angioGenesis. However, molecular mechanisms involved in SPP-induced angiogenic responses are not fully defined. Here we report the molecular mechanisms involved in SPP-induced human umbilical vein endothelial cell (HUVEC) adhesion and migration. SPP-induced HUVEC migration is potently inhibited by antisense phosphothioate oligonucleotides against EDG-1 as well as EDG-3 receptors. In addition, C3 exotoxin blocked SPP-induced cell attachment, spreading and migration on fibronectin-, vitronectin- and Matrigel-coated surfaces, suggesting that endothelial Differentiation Gene receptor signaling via the Rho pathway is critical for SPP-induced cell migration. Indeed, SPP induced Rho activation in an adherence-independent manner, whereas Rac activation was dispensible for cell attachment and focal contact formation. Interestingly, both EDG-1 and -3 receptors were required for Rho activation. Since integrins are critical for cell adhesion, migration, and angioGenesis, we examined the effects of blocking antibodies against αvβ3, β1, or β3 integrins. SPP induced Rho-dependent integrin clustering into focal contact sites, which was essential for cell adhesion, spreading and migration. Blockage of αvβ3- or β1-containing integrins inhibited SPP-induced HUVEC migration. Together our results suggest that endothelial Differentiation Gene receptor-mediated Rho signaling is required for the activation of integrin αvβ3 as well as β1-containing integrins, leading to the formation of initial focal contacts and endothelial cell migration.
-
sphingosine 1 phosphate as a ligand for the g protein coupled receptor edg 1
Science, 1998Co-Authors: Menq Jer Lee, James R Van Brocklyn, Shobha Thangada, Catherine H Liu, Arthur R Hand, Ramil Menzeleev, Sarah Spiegel, Timothy HlaAbstract:The sphingolipid metabolite sphingosine-1-phosphate (SPP) has been implicated as a second messenger in cell proliferation and survival. However, many of its biological effects are due to binding to unidentified receptors on the cell surface. SPP activated the heterotrimeric guanine nucleotide binding protein (G protein)-coupled orphan receptor EDG-1, originally cloned as Endothelial Differentiation Gene-1. EDG-1 bound SPP with high affinity (dissociation constant = 8.1 nM) and high specificity. Overexpression of EDG-1 induced exaggerated cell-cell aggregation, enhanced expression of cadherins, and formation of well-developed adherens junctions in a manner dependent on SPP and the small guanine nucleotide binding protein Rho.
Jan E Brinchmann - One of the best experts on this subject based on the ideXlab platform.
-
in vitro expansion of human mesenchymal stem cells choice of serum is a determinant of cell proliferation Differentiation Gene expression and transcriptome stability
Stem Cells, 2005Co-Authors: Aboulghassem Shahdadfar, Katrine Fronsdal, Terje Haug, Finn P Reinholt, Jan E BrinchmannAbstract:Human bone marrow mesenchymal stem cells (hMSCs) represent an appealing source of adult stem cells for cell therapy and tissue engineering, as they are easily obtained and expanded while maintaining their multilineage Differentiation potential. All current protocols for in vitro culture of hMSCs include fetal bovine serum (FBS) as nutritional supplement. FBS is an undesirable additive to cells that are expanded for therapeutic purposes in humans because the use of FBS carries the risk of transmitting viral and prion diseases and proteins that may initiate xenoGeneic immune responses. In the present study, we have therefore investigated if autologous serum (AS) or alloGeneic human serum (alloHS) could replace FBS for the expansion of hMSCs in vitro. We discovered that the choice of serum affected hMSCs at several different levels. First, hMSCs in AS proliferated markedly faster than hMSCs in FBS, whereas use of alloHS resulted in hMSC growth arrest and death. Second, hMSCs in FBS differentiated more rapidly toward mesenchymal lineages compared with hMSCs in AS. Interestingly, genome-wide microarray analysis identified several transcripts involved in cell cycle and Differentiation that were differentially regulated between hMSCs in FBS and AS. Finally, several transcripts, including some involved in cell cycle inhibition, were upregulated in hMSCs in FBS at a late passage, whereas the hMSC transcriptome in AS was remarkably stable. Thus, hMSCs may be expanded rapidly and with stGene expresin AS in the absence of growth factors, whereas FBS induces a more differentiated and less stable transcriptional profile. Stem Cells 2005;23:1357–1366
-
in vitro expansion of human mesenchymal stem cells choice of serum is a determinant of cell proliferation Differentiation Gene expression and transcriptome stability
Stem Cells, 2005Co-Authors: Aboulghassem Shahdadfar, Katrine Fronsdal, Terje Haug, Finn P Reinholt, Jan E BrinchmannAbstract:Human bone marrow mesenchymal stem cells (hMSCs) represent an appealing source of adult stem cells for cell therapy and tissue engineering, as they are easily obtained and expanded while maintaining their multilineage Differentiation potential. All current protocols for in vitro culture of hMSCs include fetal bovine serum (FBS) as nutritional supplement. FBS is an undesirable additive to cells that are expanded for therapeutic purposes in humans because the use of FBS carries the risk of transmitting viral and prion diseases and proteins that may initiate xenoGeneic immune responses. In the present study, we have therefore investigated if autologous serum (AS) or alloGeneic human serum (alloHS) could replace FBS for the expansion of hMSCs in vitro. We discovered that the choice of serum affected hMSCs at several different levels. First, hMSCs in AS proliferated markedly faster than hMSCs in FBS, whereas use of alloHS resulted in hMSC growth arrest and death. Second, hMSCs in FBS differentiated more rapidly toward mesenchymal lineages compared with hMSCs in AS. Interestingly, genome-wide microarray analysis identified several transcripts involved in cell cycle and Differentiation that were differentially regulated between hMSCs in FBS and AS. Finally, several transcripts, including some involved in cell cycle inhibition, were upregulated in hMSCs in FBS at a late passage, whereas the hMSC transcriptome in AS was remarkably stable. Thus, hMSCs may be expanded rapidly and with stable Gene expression in AS in the absence of growth factors, whereas FBS induces a more differentiated and less stable transcriptional profile.
Xavier Mayol - One of the best experts on this subject based on the ideXlab platform.
-
cycling d1 negatively regulates the expression of Differentiation Genes in ht 29 m6 mucus secreting colon cancer cells
Cancer Letters, 2009Co-Authors: Clara Mayo, Xavier MayolAbstract:HT-29 M6 colon cancer cells differentiate to a mucus-secreting phenotype in culture. We found that the pattern of cyclin D1 expression in HT-29 M6 cells did not correlate with instances of cell proliferation but was specifically induced during a deDifferentiation process following disaggregation of epithelial cell layers, even under conditions that did not allow cell cycle reentrance. Interestingly, ectopic expression of cyclin D1 in differentiated cells led to the inhibition of the transcriptional activity of Differentiation Gene promoters, such as the mucin MUC1. We thus propose that the overexpression of cyclin D1 found in colon cancer favours tumour deDifferentiation as one mechanism of tumour progression.
-
in vitro Differentiation of ht 29 m6 mucus secreting colon cancer cells involves a trychostatin a and p27kip1 inducible transcriptional program of Gene expression
Journal of Cellular Physiology, 2007Co-Authors: Clara Mayo, Josep Lloreta, Francisco X Real, Xavier MayolAbstract:Tumor cell deDifferentiation-such as the loss of cell-to-cell adhesion in epithelial tumors-is associated with tumor progression. To better understand the mechanisms that maintain carcinoma cells in a differentiated state, we have dissected in vitro Differentiation pathways in the mucus-secretor HT-29 M6 colon cancer cell line, which spontaneously differentiates in postconfluent cultures. By lowering the extracellular calcium concentration to levels that prevent intercellular adhesion and epithelial polarization, our results reveal that Differentiation is calcium-dependent and involves: (i) a process of cell cycle exit to G(0) and (ii) the induction of a transcriptional program of Differentiation Gene expression (i.e., mucins MUC1 and MUC5AC, and the apical membrane peptidase DPPIV). In calcium-deprived, non-differentiated postconfluent cultures, Differentiation Gene promoters are repressed by a trichostatin A (TSA)-sensitive mechanism, indicating that loss of Gene expression by deDifferentiation is driven by histone deacetylases (HDAC). Since TSA treatment or extracellular calcium restoration allow Gene promoter activation to similar levels, we suggest that induction of Differentiation is one mechanism of HDAC inhibitor antitumor action. Moreover, transcriptional de-repression can also be induced in non-differentiating culture conditions by overexpressing the cyclin-dependent kinase inhibitor p27(KIP1), which is normally induced during spontaneous Differentiation. Since p27(KIP1) downregulation in colon cancer is associated with poor prognosis independently of tumor cell division rates, we propose that p27 (KIP1) may prevent tumor progression by, at least in part, enhancing the expression of some Differentiation Genes. Therefore, the HT-29 M6 model allows the identification of some basic mechanisms of cancer cell Differentiation control, so far revealing HDAC and p27(KIP1) as key regulatory factors of Differentiation Gene expression.
Joe G N Garcia - One of the best experts on this subject based on the ideXlab platform.
-
protective effects of sphingosine 1 phosphate in murine endotoxin induced inflammatory lung injury
American Journal of Respiratory and Critical Care Medicine, 2004Co-Authors: Xinqi Peng, Paul M Hassoun, Saad Sammani, Bryan J Mcverry, Melissa J Burne, Hamid Rabb, David B Pearse, Rubin M Tuder, Joe G N GarciaAbstract:Our prior in vitro studies indicate that sphingosine 1-phosphate (S1P), a phospholipid angiogenic factor, produces endothelial cell barrier enhancement through ligation of endothelial Differentiation Gene family receptors. We hypothesized that S1P may reduce the vascular leak associated with acute lung injury and found that S1P infusion produced a rapid and significant reduction in lung weight gain (more than 50%) in the isolated perfused murine lung. The effect of S1P was next assessed in a murine model of LPS-mediated microvascular permeability and inflammation with marked increases in parameters of lung injury at both 6 and 24 hours after intratracheal LPS. Each parameter assessed was significantly reduced by intravenous S1P (1 μM final) and in selected experiments by the S1P analogue FTY720 (0.1 mg/kg, intraperitoneally) delivered 1 hour after LPS. S1P produced an approximately 40–50% reduction in LPS-mediated extravasation of Evans blue dye albumin, bronchoalveolar lavage protein content, and lung ti...
-
differential regulation of sphingosine 1 phosphate and vegf induced endothelial cell chemotaxis involvement of g ialpha2 linked rho kinase activity
American Journal of Respiratory Cell and Molecular Biology, 2001Co-Authors: Feng Liu, Alexander D Verin, Peiyi Wang, Regina Day, Robert P Wersto, Francis J Chrest, Denis English, Joe G N GarciaAbstract:We compared stimulus-coupling pathways involved in bovine pulmonary artery (PA) and lung microvascular endothelial cell migration evoked by sphingosine-1-phosphate (S1P), a potent bioactive lipid released from activated platelets, and by vascular endothelial growth factor (VEGF), a well-recognized angiogenic factor. S1P-induced endothelial cell migration was maximum at 1 μ M ( ∼ 8-fold increase with PA endothelium) and surpassed the maximal response evoked by either VEGF (10 ng/ml) ( ∼ 2.5-fold increase) or hepatocyte growth factor (HGF) ( ∼ 2.5-fold increase). Migration induced by S1P, but not by VEGF, was significantly inhibited by treatment with antisense oligonucleotides directed to Edg-1 and Edg-3 (endothelial Differentiation Gene) S1P receptors and by G protein modification. These strategies included pretreatment with pertussis toxin, or transfection with mini-Genes encoding a βγ subunit inhibitory peptide of the β -adrenergic receptor kinase, or an 11-amino-acid peptide that inhibits G1 α 2 signali...
Aboulghassem Shahdadfar - One of the best experts on this subject based on the ideXlab platform.
-
in vitro expansion of human mesenchymal stem cells choice of serum is a determinant of cell proliferation Differentiation Gene expression and transcriptome stability
Stem Cells, 2005Co-Authors: Aboulghassem Shahdadfar, Katrine Fronsdal, Terje Haug, Finn P Reinholt, Jan E BrinchmannAbstract:Human bone marrow mesenchymal stem cells (hMSCs) represent an appealing source of adult stem cells for cell therapy and tissue engineering, as they are easily obtained and expanded while maintaining their multilineage Differentiation potential. All current protocols for in vitro culture of hMSCs include fetal bovine serum (FBS) as nutritional supplement. FBS is an undesirable additive to cells that are expanded for therapeutic purposes in humans because the use of FBS carries the risk of transmitting viral and prion diseases and proteins that may initiate xenoGeneic immune responses. In the present study, we have therefore investigated if autologous serum (AS) or alloGeneic human serum (alloHS) could replace FBS for the expansion of hMSCs in vitro. We discovered that the choice of serum affected hMSCs at several different levels. First, hMSCs in AS proliferated markedly faster than hMSCs in FBS, whereas use of alloHS resulted in hMSC growth arrest and death. Second, hMSCs in FBS differentiated more rapidly toward mesenchymal lineages compared with hMSCs in AS. Interestingly, genome-wide microarray analysis identified several transcripts involved in cell cycle and Differentiation that were differentially regulated between hMSCs in FBS and AS. Finally, several transcripts, including some involved in cell cycle inhibition, were upregulated in hMSCs in FBS at a late passage, whereas the hMSC transcriptome in AS was remarkably stable. Thus, hMSCs may be expanded rapidly and with stGene expresin AS in the absence of growth factors, whereas FBS induces a more differentiated and less stable transcriptional profile. Stem Cells 2005;23:1357–1366
-
in vitro expansion of human mesenchymal stem cells choice of serum is a determinant of cell proliferation Differentiation Gene expression and transcriptome stability
Stem Cells, 2005Co-Authors: Aboulghassem Shahdadfar, Katrine Fronsdal, Terje Haug, Finn P Reinholt, Jan E BrinchmannAbstract:Human bone marrow mesenchymal stem cells (hMSCs) represent an appealing source of adult stem cells for cell therapy and tissue engineering, as they are easily obtained and expanded while maintaining their multilineage Differentiation potential. All current protocols for in vitro culture of hMSCs include fetal bovine serum (FBS) as nutritional supplement. FBS is an undesirable additive to cells that are expanded for therapeutic purposes in humans because the use of FBS carries the risk of transmitting viral and prion diseases and proteins that may initiate xenoGeneic immune responses. In the present study, we have therefore investigated if autologous serum (AS) or alloGeneic human serum (alloHS) could replace FBS for the expansion of hMSCs in vitro. We discovered that the choice of serum affected hMSCs at several different levels. First, hMSCs in AS proliferated markedly faster than hMSCs in FBS, whereas use of alloHS resulted in hMSC growth arrest and death. Second, hMSCs in FBS differentiated more rapidly toward mesenchymal lineages compared with hMSCs in AS. Interestingly, genome-wide microarray analysis identified several transcripts involved in cell cycle and Differentiation that were differentially regulated between hMSCs in FBS and AS. Finally, several transcripts, including some involved in cell cycle inhibition, were upregulated in hMSCs in FBS at a late passage, whereas the hMSC transcriptome in AS was remarkably stable. Thus, hMSCs may be expanded rapidly and with stable Gene expression in AS in the absence of growth factors, whereas FBS induces a more differentiated and less stable transcriptional profile.