Retinoic acid and transforming growth factor beta differentially inhibit platelet-derived-growth-factor-induced Ito-cell activation.
Ontology highlight
ABSTRACT:
SUBMITTER: Davis BH
PROVIDER: S-EPMC1151446 | biostudies-other | 1991 Aug
REPOSITORIES: biostudies-other
Similar Datasets
Project description:IntroductionThe objective of this study was to model the effects of transforming growth factor beta (TGF-beta) and platelet-derived growth factor (PDGF), both present in rheumatoid arthritis (RA) synovia, on the behavior of fibroblast-like synoviocytes (FLS) in response to pro-inflammatory cytokine (interleukin (IL)1beta, tumor necrosis factor-alpha (TNFalpha)) challenge.MethodsGene and protein expression by fibroblast-like synoviocytes in vitro was studied by quantitative Polymerase Chain Reaction (qPCR), ELISA and multiplex bead cytokine assays. Intracellular signaling pathway activation was determined by Western blot for phospho-kinases and the use of specific inhibitors.ResultsIn combination, TGF-beta and PDGF (2GF) synergistically augmented TNFalpha- or IL1beta-induced matrix metalloproteinase 3 (MMP3), IL6, IL8, and macrophage inflammatory protein 1 alpha (MIP1alpha) secretion by FLS. Other FLS-derived mediators remained unaffected. Individually, neither growth factor significantly potentiated TNFalpha or IL1beta-induced MMP3 secretion, and only slightly enhanced IL6. The effect of 2GF on TNFalpha-induced gene expression was transcriptionally mediated; blocked by imatinib mesylate; and occurred even if 2GF was added as much as four hours prior to TNFalpha. In addition, a 15-minute pulse of 2GF four hours prior to TNFalpha stimulation yielded a synergistic response. The extracellular-signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K) signaling pathways were induced for at least four hours by 2GF, as demonstrated by persistently upregulated levels of phospho-Akt and phospho-ERK. However, pharmacologic inhibitor studies demonstrated that the potentiating action of 2GF was dependent on PI3 kinase only, and not on ERK.ConclusionsThe combination of PDGF and TGF-beta dramatically potentiates FLS response to cytokines in a receptor-mediated and PI3 kinase-dependent fashion. These data suggest that 2GF contribute to synovitis by directing synovial fibroblasts toward a more aggressive phenotype in response to TNFalpha. Therefore, inhibition of growth factor signaling may constitute a complementary therapeutic approach to cytokine-targeted treatments for RA.
| S-EPMC2888219 | biostudies-literature
Project description:Platelets are a recognised potent source of transforming growth factor-β1 (TGFβ1), a cytokine known to promote wound healing and regeneration by stimulating dermal fibroblast proliferation and extracellular matrix deposition. Platelet lysate has been advocated as a novel personalised therapeutic to treat persistent wounds, although the precise platelet-derived growth factors responsible for these beneficial effects have not been fully elucidated. The aim of this study was to investigate the specific role of platelet-derived TGFβ1 in cutaneous wound healing. Using a transgenic mouse with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1fl/fl .PF4-Cre), we show for the first time that platelet-derived TGFβ1 contributes to epidermal and dermal thickening and cellular turnover after excisional skin wounding. In vitro studies demonstrate that human dermal fibroblasts stimulated with platelet lysate containing high levels of platelet-derived TGFβ1 did not exhibit enhanced collagen deposition or proliferation, suggesting that platelet-derived TGFβ1 is not a key promoter of these wound healing processes. Interestingly, human keratinocytes displayed enhanced TGFβ1-driven proliferation in response to platelet lysate, reminiscent of our in vivo findings. In summary, our novel findings define and emphasise an important role of platelet-derived TGFβ1 in epidermal remodelling and regeneration processes during cutaneous wound healing.
| S-EPMC7216944 | biostudies-literature
Project description:Transforming growth factor beta (TGF-beta) and platelet-derived growth factor A (PDGFAlpha) play a central role in tissue morphogenesis and repair, but their interplay remain poorly understood. The nuclear factor I C (NFI-C) transcription factor has been implicated in TGF-beta signaling, extracellular matrix deposition, and skin appendage pathologies, but a potential role in skin morphogenesis or healing had not been assessed. To evaluate this possibility, we performed a global gene expression analysis in NFI-C(-/-) and wild-type embryonic primary murine fibroblasts. This indicated that NFI-C acts mostly to repress gene expression in response to TGF-beta1. Misregulated genes were prominently overrepresented by regulators of connective tissue inflammation and repair. In vivo skin healing revealed a faster inflammatory stage and wound closure in NFI-C(-/-) mice. Expression of PDGFA and PDGF-receptor alpha were increased in wounds of NFI-C(-/-) mice, explaining the early recruitment of macrophages and fibroblasts. Differentiation of fibroblasts to contractile myofibroblasts was also elevated, providing a rationale for faster wound closure. Taken together with the role of TGF-beta in myofibroblast differentiation, our results imply a central role of NFI-C in the interplay of the two signaling pathways and in regulation of the progression of tissue regeneration.
| S-EPMC2772573 | biostudies-literature
Project description:The intracellular signal transduction pathways that mediate the stimulatory effects of platelet-derived growth factor (PDGF)-BB and transforming growth factor (TGF)-beta on hyaluronan biosynthesis in human fibroblasts were investigated. The stimulatory effects of both PDGF-BB and TGF-beta 1 were dependent on protein kinase C (PKC), since the PKC inhibitor calphostin C inhibited the stimulation by the growth factors. Direct activation of PKC by phorbol 12-myristate 13-acetate (PMA) also stimulated hyaluronan production, and the combination of either PDGF-BB or TGF-beta 1 and PMA gave an increased effect. One possible mechanism for activation of PKC is via induction of phospholipase C (PLC) activity; U-17322, an inhibitor of PLC-gamma, was found to inhibit partially PDGF-BB-stimulated hyaluronan synthesis. PDGF-BB is known to activate PLC-gamma through tyrosine phosphorylation; however, a PDGF beta-receptor mutant unable to interact with and activate PLC-gamma was still able to mediate induction of hyaluronan biosynthesis, indicating that PDGF-mediated stimulation is not entirely dependent on PLC-gamma. The stimulations by PDGF-BB and TGF-beta 1 were partly dependent on protein synthesis, since parts of the effects were inhibited by cycloheximide; in contrast, the effects mediated by PMA were not. Our results indicate that PKC is involved in the transduction of the effects of growth factors on hyaluronan biosynthesis, and that the effects involve direct or indirect activation of existing hyaluronan synthetase molecules, as well as induction of new enzyme molecules.
| S-EPMC1136722 | biostudies-other
Project description:Mutations in the gene for the latent transforming growth factor beta binding protein 4 (LTBP4) cause autosomal recessive cutis laxa type 1C. To understand the molecular disease mechanisms of this disease, we investigated the impact of LTBP4 loss on transforming growth factor beta (TGFβ) signaling. Despite elevated extracellular TGFβ activity, downstream signaling molecules of the TGFβ pathway, including pSMAD2 and pERK, were down-regulated in LTBP4 mutant human dermal fibroblasts. In addition, TGFβ receptors 1 and 2 (TGFBR1 and TGFBR2) were reduced at the protein but not at the ribonucleic acid level. Treatment with exogenous TGFβ1 led to an initially rapid increase in SMAD2 phosphorylation followed by a sustained depression of phosphorylation and receptor abundance. In mutant cells TGFBR1 was co-localized with lysosomes. Treatment with a TGFBR1 kinase inhibitor, endocytosis inhibitors or a lysosome inhibitor, normalized the levels of TGFBR1 and TGFBR2. Co-immunoprecipitation demonstrated a molecular interaction between LTBP4 and TGFBR2. Knockdown of LTBP4 reduced TGFβ receptor abundance and signaling in normal cells and supplementation of recombinant LTBP4 enhanced these measures in mutant cells. In a mouse model of Ltbp4 deficiency, reduced TGFβ signaling and receptor levels were normalized upon TGFBR1 kinase inhibitor treatment. Our results show that LTBP4 interacts with TGFBR2 and stabilizes TGFβ receptors by preventing their endocytosis and lysosomal degradation in a ligand-dependent and receptor kinase activity-dependent manner. These findings identify LTBP4 as a key molecule required for the stability of the TGFβ receptor complex, and a new mechanism by which the extracellular matrix regulates cytokine receptor signaling.
| S-EPMC4476448 | biostudies-literature
Project description:BackgroundVascular endothelial growth factor (VEGF)-mediated angiogenesis mediates tumour growth and metastasis. Meningiomas are primarily benign, slow-growing, highly vascularised tumours. Aside from VEGF, there is little data on the function of major angiogenic proteins in meningiomas.MethodsThe VEGFA, platelet-derived growth factor B (PDGFB), and their respective receptors - VEGF receptor 2 (KDR) and PDGF receptor β (PDGFRβ) - were quantified using real-time PCR and a TaqMan Protein Assay in meningiomas in vivo and in vitro. The effect of VEGFA and PDGFB on cell proliferation and the tyrosine phosphorylation of PDGFRβ were examined.ResultsMost meningiomas displayed no KDR protein expression but elevated PDGFRβ levels. Exogenous VEGFA stimulation significantly increased cell proliferation. The PDGFRβ inhibition before stimulation with VEGFA abolished the proliferative stimuli. The VEGFA induced concentration-dependent PDGFRβ tyrosine phosphorylation comparable to PDGFB-induced PDGFRβ tyrosine phosphorylation. The PDGFRβ inhibitors gambogic acid, sunitinib, and tandutinib equally impaired the migration of meningioma cells. In addition, gambogic acid suppressed the VEGFA-induced PDGFRβ tyrosine phosphorylation.ConclusionCollectively, our data suggest that VEGFA primarily regulates VEGF-mediated migration through PDGFRβ in meningiomas. The inhibitory effect of gambogic acid and tandutinib against meningioma growth in vitro suggests that selective PDGFRβ inhibitors, in combination with VEGF inhibitors, should be evaluated further as potential therapies for recurrent and malignant meningiomas.
| S-EPMC3493872 | biostudies-literature
Project description:PurposeTumor-associated macrophages (TAMs) originate from monocytes and differentiate into mature macrophages. The interaction between cancer cells and TAMs promotes tumor growth and suppresses immunosurveillance. However, this phenomenon has seldom been observed in ampullary cancer.Patients and methodsTAMs in ampullary cancer were investigated using immunohistochemical (IHC) staining of cancer tissues. Bioinformatic analysis of data from the Gene Expression Omnibus (GEO) database revealed transforming growth factor-beta (TGF-β) signaling in ampullary cancer. The complementary DNA microarray of cancer was compared with adjacent normal duodenum and enzyme-linked immunosorbent assay of serum was used to verify TGF-β signaling in patients. The THP-1 cell line was activated in vitro to imitate M2 TAMs. ClueGo and CluePedia software were operated to simulate TGF-β-related networks in ampullary cancer.ResultsThe IHC study revealed that the majority of TAMs inside ampullary cancer were cluster of differentiation (CD)163+ cells and that the expression of mature CD68+ macrophages was correlated with advanced cancer stage. Bioinformatics analysis revealed that TGF-β and its downstream signaling were significantly upregulated. To verify our bioinformatics-derived predictions, we performed several experiments and demonstrated that increased TGF-β expression was detected in the cDNA microarray. Higher serum levels of TGF-β were correlated with fewer CD68+ and more inducible nitric oxide synthase macrophages in ampullary cancer. Treatment with TGF-β induced modulation of THP-1-derived macrophages.ConclusionThe present study demonstrates that TGF-β modulates macrophage activity in ampullary cancer. Targeting TGF-β could be an approach to activating immunosurveillance.
| S-EPMC7423398 | biostudies-literature
Project description:IntroductionIdiopathic pulmonary fibrosis (IPF) is a chronic progressive disease with very few effective treatments. The key effector cells in fibrosis are believed to be fibroblasts, which differentiate to a contractile myofibroblast phenotype with enhanced capacity to proliferate and produce extracellular matrix. The role of the lung epithelium in fibrosis is unclear. While there is evidence that the epithelium is disrupted in IPF, it is not known whether this is a cause or a result of the fibroblast pathology. We hypothesized that healthy epithelial cells are required to maintain normal lung homeostasis and can inhibit the activation and differentiation of lung fibroblasts to the myofibroblast phenotype. To investigate this hypothesis, we employed a novel co-culture model with primary human lung epithelial cells and fibroblasts to investigate whether epithelial cells inhibit myofibroblast differentiation.Measurements and main resultsIn the presence of transforming growth factor (TGF)-β, fibroblasts co-cultured with epithelial cells expressed significantly less α-smooth muscle actin and collagen and showed marked reduction in cell migration, collagen gel contraction, and cell proliferation compared to fibroblasts grown without epithelial cells. Epithelial cells from non-matching tissue origins were capable of inhibiting TGF-β induced myofibroblast differentiation in lung, keloid and Graves' orbital fibroblasts. TGF-β promoted production of prostaglandin (PG) E2 in lung epithelial cells, and a PGE2 neutralizing antibody blocked the protective effect of epithelial cell co-culture.ConclusionsWe provide the first direct experimental evidence that lung epithelial cells inhibit TGF-β induced myofibroblast differentiation and pro-fibrotic phenotypes in fibroblasts. This effect is not restricted by tissue origin, and is mediated, at least in part, by PGE2. Our data support the hypothesis that the epithelium plays a crucial role in maintaining lung homeostasis, and that damaged and/ or dysfunctional epithelium contributes to the development of fibrosis.
| S-EPMC4527711 | biostudies-literature
Project description:The basic amino acid-specific proprotein convertase 5/6 (PC5/6) is an essential secretory protease, as knock-out mice die at birth and exhibit multiple homeotic transformation defects, including impaired bone morphogenesis and lung structure. Some of the observed defects were attributed to impaired processing of the TGFβ-like growth differentiating factor 11 precursor (proGdf11). In this work we present evidence that the latent TGFβ-binding proteins 2 and 3 (LTBP-2 and -3) inhibit the extracellular processing of proGdf11 by PC5/6A. This is partly due to the binding of LTBPs in the endoplasmic reticulum to the zymogen proPC5/6A, thus allowing the complex to exit the endoplasmic reticulum and be sequestered as an inactive zymogen in the extracellular matrix but not at the cell surface. This results in lower levels of PC5/6A in the media, without affecting those of PACE4, Furin, or a soluble form of PC7. The secreted soluble protease-specific activity of PC5/6A or a variant lacking the C-terminal Cys-rich domain (PC5/6-ΔCRD) is significantly decreased when co-expressed with LTBPs in cells. A similar enzymatic inhibition seems to apply to PACE4 and Furin. In situ hybridization analyses revealed extensive co-localization of PC5/6 and LTBP-3 mRNAs in mice at embryonic day 15.5 and post partum day 1. In conclusion, this is the first time that a zymogen of the proprotein convertases was shown to exit the endoplasmic reticulum in the presence of LTBPs, representing a potential novel mechanism for the regulation of PC5/6A activity, e.g. in tissues such as bone and lung where LTBP-3 and PC5/6 co-localize.
| S-EPMC3190714 | biostudies-literature
Project description:TGF-β is a pleiotropic cytokine that regulates a wide range of cellular actions and pathophysiological processes. TGF-β signaling is spatiotemporally fine-tuned. As a key negative regulator of TGF-β signaling, Smad7 exerts its inhibitory effects by blocking receptor activity, inducing receptor degradation or interfering with Smad-DNA binding. However, the functions and the molecular mechanisms underlying the actions of Smad7 in TGF-β signaling are still not fully understood. In this study we report a novel mechanism whereby Smad7 antagonizes TGF-β signaling at the Smad level. Smad7 oligomerized with R-Smad proteins upon TGF-β signaling and directly inhibited R-Smad activity, as assessed by Gal4-luciferase reporter assays. Mechanistically, Smad7 competes with Smad4 to associate with R-Smads and recruits the E3 ubiquitin ligase NEDD4L to activated R-Smads, leading to their polyubiquitination and proteasomal degradation. Similar to the R-Smad-Smad4 oligomerization, the interaction between R-Smads and Smad7 is mediated by their mad homology 2 (MH2) domains. A positive-charged basic region including the L3/β8 loop-strand module and adjacent amino acids in the MH2 domain of Smad7 is essential for the interaction. These results shed new light on the regulation of TGF-β signaling by Smad7.
| S-EPMC4697173 | biostudies-literature