Down-Regulation of Toll-Like Receptor 4 Expression in Transforming Growth Factor β1 Treated Murine Dendritic Cells: Implications of Maturation Resistant to Lipopolysaccharide.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3803-3803
Author(s):  
Maofang Lin ◽  
Haibo Mou ◽  
Hong Cen

Abstract Evidences accumulated that immature dendritic cell (iDC) could inhibit alloantigen-specific T cell responses and prolong the survival time of allografts. However, the tolerogenic properties of these iDCs were often unstable or inconsistent because of in vivo maturation, such as lipopolysaccharide (LPS) stimulating. Toll-like receptor 4(TLR4) has been reported to act as a receptor for LPS and LPS can stimulate iDC to mature DC (mDC) via TLR4 signal transduction pathway. In this study, we investigated the effects of transforming growth factor β1 on murine bone marrow derived DCs. Murine bone marrow cells were cultured with GM-CSF and TGF-β1 to generate TGF-β1 treated DCs (TGFβ-DCs). Compared to iDCs cultured by GM-CSF alone, the TGFβ-DCs had no significant alterations in ultrastructure after LPS stimulation. Surface expression of CD80, CD86, CD40, MHC-II were inhibited by addition of TGF-β1, especially in CD80, CD86 (p<0.05). Furthermore, the iDCs were sensitive to further maturation in response to LPS by showing increased levels of MHC class II, CD80, CD86 and CD40. In marked contrast, TGF-β1 prevented this LPS-mediated maturation and maintained the cells in the immature state, with low levels of surface costimulatory molecules expression. Using BrdU incorporation method, after 96 h mix lymphocyte reaction, TGFβ-DCs had weaker allogeneic stimulating capacity than iDCs. Importantly, LPS stimulating strongly promoted the allostimulatory capacity of iDCs, whereas only slightly affected TGFβ-DCs. TGFβ-DCs also showed decreased IL-12p70 production and impaired NF-κB activation after LPS stimulation. We also found the expression of TLR4 mRNA on TGFβ-DCs was weaker than that on iDCs by RT-PCR. Moreover, the results of flow cytometry revealed the positive expression percentages of TLR4/MD2 complex on iDCs and TGFβ-DCs were (51.8±3.89% vs. 15.7±4.13%, p<0.01) and the mean fluorescence intensities (MFIs) were (2.37±0.26 vs. 1.36±0.17, p<0.05). These results agreed with previous findings that TGFβ-DCs responded weakly to LPS. In summary, TGFβ-DC is resistant to maturation stimulus (LPS) and might have some correlation with the down-modulation of TLR4 expression.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3861-3861
Author(s):  
Haibo Mou ◽  
Maofang Lin ◽  
He Huang

Abstract We have demonstrated that transforming growth factor-β1(TGF-β1) inhibits the maturation of mouse bone marrow derived dendritic cells (DCs). TGF-β1 treated DCs (TGFβ-DCs) are resistant to maturation stimulus -lipopolysaccharide (LPS) and might have some correlation with the down-modulation of Toll-like receptor 4 (TLR4) expression. It was known TLR4 binds LPS from Gram-negative bacteria, triggering signaling pathways that lead to the activation of NF-κB, ERK1/2 and p38 MAPK and ensuing gene expression of proinflammatory factors. In the current study, we further estimated the activities of NF-κB, ERK1/2 and p38 proteins involved in TLR4 signaling pathway. Using EMSA method, we found the NF-κB DNA binding activity in immature DCs (imDCs) was significantly increased in response to LPS, but addition of TGF-β1 to DCs inhibited NF-κB binding. Moreover, TGF-β1 was effective in suppressing LPS-induced activation of ERK1/2 and p38 kinase, the level of phosphorylation of ERK1/2 and p38 kinase were lower than imDCs measured by Western Blot. After treatment of imDCs and TGFβ-DCs with LPS for 24 h, the production of IL-12p70 of TGFβ-DCs was significantly less than that of imDCs(115.4±15.2 pg/ml vs 517.0±29.7 pg/ml, P&lt;0.01), but the level of Th2 cytokine-IL-10 was elevated(132.1±17.5 pg/ml vs 75.1±16.6 pg/ml, P&lt;0.05), indicating that exposure to TGF-β1 impaired the capability of DCs to produce high amounts of bioactive IL-12p70. According to the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), the expressions of chemokines MIP-1α mRNA on TGFβ-DCs after LPS stimulation were lower than imDCs at each time point. The lower expressions of MCP-1 and IP-10 on TGFβ-DCs at irregular pattern after LPS treatment, whereas the expressions RANTES were no different. Hence, the results suggested TGF-β1 maybe directly inhibit TLR4 expression on DCs, and then interfere with the activity of downstream key proteins, such as NF-κB, ERK1/2 and p38. Ultimately, TGF-β1 treated DCs were resistance to LPS, down-regulated the expression of costimulatory molecular on DCs and decreased the secretion of inflammatory cytokines.


Blood ◽  
1999 ◽  
Vol 93 (10) ◽  
pp. 3225-3232 ◽  
Author(s):  
Masafumi Ogata ◽  
Yi Zhang ◽  
Yong Wang ◽  
Meiji Itakura ◽  
Yan-yun Zhang ◽  
...  

Dendritic cells (DCs) are highly specialized antigen-presenting cells that distribute widely in all organs. DCs initiate the primary immune response and activate naive T cells and B cells responsible for the acquired immunity. In this study, CCR7 mRNA was proved to be expressed in DCs and their precursors derived from murine bone marrow-derived hematopoietic progenitor cells (HPCs), whereas CCR1 mRNA was expressed in both CD11b−/dullCD11c+ and CD11b+hiCD11c+ DC precursors. CCR6 mRNA was not detected in any murine DC populations. In agreement with the chemokine receptor mRNA expression by each population in the DC differentiation pathway, SLC (also termed as MIP-3β), one of the ligands for CCR7, strongly and selectively chemoattracted both CD11b−/dullCD11c+ and CD11b+hiCD11c+ DC precursors (days 6 to 7) and more mature DCs (days 13 to 14). We have recently found that transforming growth factor-β1 (TGF-β1), a cytokine that is essential for the appearance of Langerhans cells in the skin, polarizes murine HPCs to generate Langerhans-like cells through monocyte/macrophage differentiation pathway. We observed here that TGF-β1 not only inhibited the expression of CCR7 in DCs and DC precursors derived from HPCs, but also inhibited the migration of these cells in response to SLC. This is the first report describing the chemokine and chemokine receptors responsible for murine DC migration and downregulation of DC migration by TGF-β1.


Blood ◽  
2005 ◽  
Vol 106 (2) ◽  
pp. 485-493 ◽  
Author(s):  
Sunanda Basu ◽  
Hal E. Broxmeyer

Abstract Disruption of stromal cell-derived factor-1 (SDF-1/CXCL12 [CXC chemokine ligand 12]) interaction leads to mobilization of stem/progenitor cells from bone marrow to circulation. However, prolonged exposure of CD34+ cells to SDF-1 desensitizes them to SDF-1. So how do cells remain responsive to SDF-1 in vivo when they are continuously exposed to SDF-1? We hypothesized that one or more mechanisms mediated by cytokines exist that could modulate SDF-1 responsiveness of CD34+ cells and the desensitization process. We considered transforming growth factor-β1 (TGF-β1) a possible candidate, since TGF-β1 has effects on CD34+ cells and is produced by stromal cells, which provide niches for maintenance and proliferation of stem/progenitor cells. TGF-β1 significantly restored SDF-1–induced chemotaxis and sustained adhesion responses in cord blood CD34+ cells preexposed to SDF-1. Effects of TGF-β1 were dependent on the dose and duration of TGF-β1 pretreatment. Phosphorylation of extracellular signal-regulated kinase 1 (Erk1)/Erk2 was implicated in TGF-β1 modulation of migratory and adhesion responses to SDF-1. Our results indicate that low levels of TGF-β1 can modulate SDF-1 responsiveness of CD34+ cells and thus may facilitate SDF-1–mediated retention and nurturing of stem/progenitor cells in bone marrow.


Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1208-1220 ◽  
Author(s):  
Yi Zhang ◽  
Yan-yun Zhang ◽  
Masafumi Ogata ◽  
Pan Chen ◽  
Akihisa Harada ◽  
...  

We have recently demonstrated that CD11b−/dullCD11c+ and CD11b+hiCD11c+ dendritic cell (DC) precursor subsets represent two distinct DC differentiation pathways from murine bone marrow lineage-phenotype negative (Lin−)c-kit+ hematopoietic progenitor cells (HPCs) stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) + stem cell factor (SCF) + tumor necrosis factor  (TNF). We show here that transforming growth factor-β1 (TGF-β1) significantly inhibits the generation of these CD11b−/dullCD11c+ and CD11b+hiCD11c+ DC precursors. Phenotypically, this inhibitory effect was accompanied by markedly suppressed expression of Ia and CD86 antigens as well as major histocompatibility complex (MHC) class II transactivator (CIITA) and CC-chemokine receptor 7 (CCR7) mRNAs in Lin−c-kit+ HPC cultures stimulated with GM-CSF + SCF + TNF at day 6. TGF-β1 could also suppress mature DC differentiation from CD11b+hiCD11c+ DC precursors, but not the differentiation from CD11b−/dullCD11c+ DC precursors. In the absence of TNF, TGF-β1 markedly suppressed the expression of CIITA and CCR7 mRNAs in GM-CSF + SCF-stimulated Lin−c-kit+ HPCs at either day 6 or day 12 and induced the differentiation solely into monocytes/macrophages as evident in morphology, active phagocytic, and endocytic activities. These cells expressed high levels of F4/80 and E-cadherin antigens, but low or undetectable levels of Ia, CD86, and CD40 molecules. However, upon the stimulation with TNF + GM-CSF, these cells could further differentiate into mature DCs expressing high levels of Ia and E-cadherin, characteristics for Langerhans cells (LCs), and gained the capacity of enhancing allogenic MLR. Taken together, all of these findings suggest that TGF-β1 polarizes murine HPCs to generate LC-like DCs through a monocyte/macrophage differentiation pathway.


Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1961-1970 ◽  
Author(s):  
Sumio Sakamaki ◽  
Yasuo Hirayama ◽  
Takuya Matsunaga ◽  
Hiroyuki Kuroda ◽  
Toshiro Kusakabe ◽  
...  

Abstract The present study was designed to test the concept that platelets release a humoral factor that plays a regulatory role in megakaryopoiesis. The results showed that, among various hematoregulatory cytokines examined, transforming growth factor-β1 (TGF-β1) was by far the most potent enhancer of mRNA expression of bone marrow stromal thrombopoietin (TPO), a commitment of lineage specificity. The TPO, in turn, induced TGF-β receptors I and II on megakaryoblasts at the midmegakaryopoietic stage; at this stage, TGF-β1 was able to arrest the maturation of megakaryocyte colony-forming units (CFU-Meg). This effect was relatively specific when compared with its effect on burst-forming unit-erythroid (BFU-E) or colony-forming unit–granulocyte-macrophage (CFU-GM). In patients with idiopathic thrombocytopenic purpura (ITP), the levels of both TGF-β1 and stromal TPO mRNA were correlatively increased and an arrest of megakaryocyte maturation was observed. These in vivo findings are in accord with the aforementioned in vitro results. Thus, the results of the present investigation suggest that TGF-β1 is one of the pathophysiological feedback regulators of megakaryopoiesis.


Blood ◽  
2003 ◽  
Vol 102 (6) ◽  
pp. 1978-1984 ◽  
Author(s):  
Natalia Wright ◽  
Teresa Laín de Lera ◽  
Carelia García-Moruja ◽  
Rosa Lillo ◽  
Félix García-Sánchez ◽  
...  

Abstract Chemokine stromal cell–derived factor-1 (SDF-1) is expressed by bone marrow (BM) stromal cells and plays key roles in BM cell migration. Modulation of its expression could affect the migratory capacity of cells trafficking the BM, such as hematopoietic progenitor and leukemic cells. Transforming growth factor-β1 (TGF-β1) is present in the BM environment and constitutes a pivotal molecule controlling BM cell proliferation and differentiation. We used the BM stromal cell line MS-5 as a model to investigate whether SDF-1 expression constitutes a target for TGF-β1 regulation and its functional consequences. We show here that TGF-β1 down-regulates SDF-1 expression, both at the mRNA level, involving a decrease in transcriptional efficiency, and at the protein level, as detected in lysates and supernatants from MS-5 cells. Reduction of SDF-1 in supernatants from TGF-β1–treated MS-5 cells correlated with decreased, SDF-1–dependent, chemotactic, and transendothelial migratory responses of the BM model cell lines NCI-H929 and Mo7e compared with their responses to supernatants from untreated MS-5 cells. In addition, supernatants from TGF-β1–exposed MS-5 cells had substantially lower efficiency in promoting integrin α4β1–mediated adhesion of NCI-H929 and Mo7e cells to soluble vascular cell adhesion molecule-1 (sVCAM-1) and CS-1/fibronectin than their untreated counterparts. Moreover, human cord blood CD34+ hematopoietic progenitor cells displayed SDF-1–dependent reduced responses in chemotaxis, transendothelial migration, and up-regulation of adhesion to sVCAM-1 when supernatants from TGF-β1–treated MS-5 cells were used compared with supernatants from untreated cells. These data indicate that TGF-β1–controlled reduction in SDF-1 expression influences BM cell migration and adhesion, which could affect the motility of cells trafficking the bone marrow.


Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1208-1220 ◽  
Author(s):  
Yi Zhang ◽  
Yan-yun Zhang ◽  
Masafumi Ogata ◽  
Pan Chen ◽  
Akihisa Harada ◽  
...  

Abstract We have recently demonstrated that CD11b−/dullCD11c+ and CD11b+hiCD11c+ dendritic cell (DC) precursor subsets represent two distinct DC differentiation pathways from murine bone marrow lineage-phenotype negative (Lin−)c-kit+ hematopoietic progenitor cells (HPCs) stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) + stem cell factor (SCF) + tumor necrosis factor  (TNF). We show here that transforming growth factor-β1 (TGF-β1) significantly inhibits the generation of these CD11b−/dullCD11c+ and CD11b+hiCD11c+ DC precursors. Phenotypically, this inhibitory effect was accompanied by markedly suppressed expression of Ia and CD86 antigens as well as major histocompatibility complex (MHC) class II transactivator (CIITA) and CC-chemokine receptor 7 (CCR7) mRNAs in Lin−c-kit+ HPC cultures stimulated with GM-CSF + SCF + TNF at day 6. TGF-β1 could also suppress mature DC differentiation from CD11b+hiCD11c+ DC precursors, but not the differentiation from CD11b−/dullCD11c+ DC precursors. In the absence of TNF, TGF-β1 markedly suppressed the expression of CIITA and CCR7 mRNAs in GM-CSF + SCF-stimulated Lin−c-kit+ HPCs at either day 6 or day 12 and induced the differentiation solely into monocytes/macrophages as evident in morphology, active phagocytic, and endocytic activities. These cells expressed high levels of F4/80 and E-cadherin antigens, but low or undetectable levels of Ia, CD86, and CD40 molecules. However, upon the stimulation with TNF + GM-CSF, these cells could further differentiate into mature DCs expressing high levels of Ia and E-cadherin, characteristics for Langerhans cells (LCs), and gained the capacity of enhancing allogenic MLR. Taken together, all of these findings suggest that TGF-β1 polarizes murine HPCs to generate LC-like DCs through a monocyte/macrophage differentiation pathway.


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