Hypoxia induces differentiation of pulmonary artery adventitial fibroblasts into myofibroblasts

2004 ◽  
Vol 286 (2) ◽  
pp. C416-C425 ◽  
Author(s):  
Megan Short ◽  
Raphel A. Nemenoff ◽  
W. Michael Zawada ◽  
Kurt R. Stenmark ◽  
Mita Das
Keyword(s):  
Pulmonary Artery ◽  
Signaling Pathways ◽  
Promoter Activity ◽  
Transforming Growth Factor ◽  
Essential Feature ◽  
Smooth Muscle Actin ◽  
Neutralizing Antibody ◽  
Luciferase Reporter ◽  
Transcriptional Level ◽  
Adventitial Fibroblasts

Activation of the α-smooth muscle actin (α-SMA) gene during the conversion of fibroblasts into myofibroblasts is an essential feature of various fibrotic conditions. Microvascular compromise and thus local environmental hypoxia are important components of the fibrotic response. The present study was thus undertaken to test the hypothesis that hypoxia can induce transdifferentiation of vascular fibroblasts into myofibroblasts and also to evaluate potential signaling mechanisms governing this process. We found that hypoxia significantly upregulates α-SMA protein levels in bovine pulmonary artery adventitial fibroblasts. Increased α-SMA expression is controlled at the transcriptional level because the α-SMA gene promoter activity, assayed via a luciferase reporter, was markedly increased in transfected fibroblasts exposed to hypoxia. Hypoxic induction of the α-SMA gene was mimicked by overexpression of constitutively active Gαi2 (αi2Q205L) but not Gα16 (α-16Q212L). Blockade of hypoxia-induced α-SMA expression with pertussis toxin, a Gαi antagonist, confirmed a role for Gαi in the hypoxia-induced transdifferentiation process. c-Jun NH2-terminal kinase (JNK) inhibitor II and SB202190, but not U0126, also attenuated α-SMA expression in hypoxic fibroblasts, suggesting the importance of JNK in the differentiation process. Hypoxia-induced increase in bromodeoxyuridine incorporation, which occurred concomitantly with hypoxia-induced differentiation, was blocked by U0126, suggesting that DNA synthesis and α-SMA expression take place through simultaneously activated parallel signaling pathways. Neutralizing antibody against transforming growth factor-β1 blocked only 30% of the hypoxia-induced α-SMA promoter activity. Taken together, our results suggest that hypoxia induces differentiation of vascular fibroblasts into myofibroblasts by upregulating the expression of α-SMA, and this increase in α-SMA level occurs through Gαi- and JNK-dependent signaling pathways.

scholarly journals Fucoxanthin Inhibits Myofibroblast Differentiation and Extracellular Matrix Production in Nasal Polyp-Derived Fibroblasts via Modulation of Smad-Dependent and Smad-Independent Signaling Pathways

Marine Drugs ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. 323 ◽  
Author(s):  
Hyun Jung ◽  
Dae-Sung Lee ◽  
Seong Park ◽  
Jung Choi ◽  
Won-Kyo Jung ◽  
...  
Keyword(s):  
Western Blot ◽  
Signaling Pathways ◽  
Nasal Polyp ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Type I ◽  
Molecular Signaling ◽  
Tgf Β1

Nasal polyps (NPs) are a multifactorial disorder associated with a chronic inflammatory state of the nasal mucosa. Fucoxanthin (Fx) is a characteristic orange carotenoid obtained from brown algae and has diverse immunological properties. The present study investigated whether Fx inhibits fibrosis-related effects in nasal polyp-derived fibroblasts (NPDFs) and elucidated the molecular signaling pathways involved. The production of collagen type I (Col-1) was investigated in NP tissue via immunohistochemistry and western blot analysis. NPDFs were treated with transforming growth factor (TGF)-β1 (1 ng/mL) in the presence or absence of Fx (5–30 µM). The levels of α-smooth muscle actin (α-SMA), Col-1, and phosphorylated (p)-Smad 2/3, signal protein-1 (SP-1), MAPKs (mitogen-activated protein kinases), and Akt were measured by western blot analysis. The expression of Col-1 was detected in NP tissues. TGF-β1 stimulated the production of α-SMA and Col-1, and stimulated the contraction of collagen gel. However, pretreatment with Fx attenuated these effects. Furthermore, these inhibitory effects were mediated through modulation of both Smad 2/3 and Akt/SP-1 signaling pathways in TGF-β1-induced NPDFs. The results from the present study suggest that Fx may be a novel anti-fibrotic agent for the treatment of NP formation.

scholarly journals Microparticles as Potential Mediators of High Glucose-Induced Renal Cell Injury

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 348 ◽  
Author(s):  
Ravindran ◽  
Pasha ◽  
Agouni ◽  
Munusamy
Keyword(s):  
Er Stress ◽  
Signaling Pathways ◽  
Transforming Growth Factor Beta ◽  
High Glucose ◽  
Cell Injury ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Epithelial Mesenchymal Transition ◽  
Smooth Muscle Actin ◽  
Mesenchymal Transition

Diabetic nephropathy (DN) is the most common cause of chronic kidney disease worldwide. Activation of signaling pathways such as the mammalian target of rapamycin (mTOR), extracellular signal-regulated kinases (ERK), endoplasmic reticulum (ER) stress, transforming growth factor-beta (TGF-β), and epithelial-mesenchymal transition (EMT), are thought to play a significant role in the etiology of DN. Microparticles (MPs), the small membrane vesicles containing bioactive signals shed by cells upon activation or during apoptosis, are elevated in diabetes and were identified as biomarkers in DN. However, their exact role in the pathophysiology of DN remains unclear. Here, we examined the effect of MPs shed from renal proximal tubular cells (RPTCs) exposed to high glucose conditions on naïve RPTCs in vitro. Our results showed significant increases in the levels of phosphorylated forms of 4E-binding protein 1 and ERK1/2 (the downstream targets of mTOR and ERK pathways), phosphorylated-eIF2α (an ER stress marker), alpha smooth muscle actin (an EMT marker), and phosphorylated-SMAD2 and nuclear translocation of SMAD4 (markers of TGF-β signaling). Together, our findings indicate that MPs activate key signaling pathways in RPTCs under high glucose conditions. Pharmacological interventions to inhibit shedding of MPs from RPTCs might serve as an effective strategy to prevent the progression of DN.

scholarly journals β-Catenin/Smad3 Interaction Regulates Transforming Growth Factor-β-Induced Epithelial to Mesenchymal Transition in the Lens

2019 ◽  
Vol 20 (9) ◽  
pp. 2078 ◽  
Author(s):  
Aftab Taiyab ◽  
Julie Holms ◽  
Judith A. West-Mays
Keyword(s):  
Growth Factor ◽  
Signaling Pathways ◽  
Epithelial To Mesenchymal Transition ◽  
Vision Loss ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Ex Vivo ◽  
Smooth Muscle Actin ◽  
Posterior Capsular Opacification ◽  
Mesenchymal Transition

Cataracts are the leading cause of blindness worldwide. Although surgery is a successful method to restore vision loss due to cataracts, post-surgical complications can occur, such as secondary cataracts, also known as posterior capsular opacification (PCO). PCO arises when lens epithelial cells (LEC) are left behind in the capsular bag following surgery and are induced to undergo epithelial to mesenchymal transition (EMT). Following EMT, LEC morphology and phenotype are altered leading to a loss of transparency and vision. Transforming growth factor (TGF)-β-induced signaling through both canonical, TGF-β/Smad, and non-canonical, β-catenin/Wnt and Rho/ROCK/MRTF-A, pathways have been shown to be involved in lens EMT, and thus PCO. However, the interactions between these signaling pathways in the lens have not been thoroughly explored. In the current study we use rat LEC explants as an ex vivo model, to examine the interplay between three TGF-β-mediated pathways using α-smooth muscle actin (α-SMA) as a molecular marker for EMT. We show that Smad3 inhibition via SIS3 prevents nuclear translocation of β-catenin and MRTF-A, and α-SMA expression, suggesting a key role of Smad3 in regulation of MRTF-A and β-catenin nuclear transport in LECs. Further, we demonstrate that inhibition of β-catenin/CBP interaction by ICG-001 decreased the amount of phosphorylated Smad3 upon TGF-β stimulation in addition to significantly decreasing the expression levels of TGF-β receptors, TBRII and TBRI. Overall, our findings demonstrate interdependence between the canonical and non-canonical TGF-β-mediated signaling pathways controlling EMT in the lens.

scholarly journals Pharmacological inhibition of autophagy by 3-MA attenuates hyperuricemic nephropathy

2018 ◽  
Vol 132 (21) ◽  
pp. 2299-2322 ◽  
Author(s):  
Jinfang Bao ◽  
Yingfeng Shi ◽  
Min Tao ◽  
Na Liu ◽  
Shougang Zhuang ◽  
...  
Keyword(s):  
Growth Factor ◽  
Signaling Pathways ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Growth Factor Receptor ◽  
Nuclear Factor Κb ◽  
Transforming Growth Factor Β1 ◽  
Renal Tissue ◽  
Tgf Β1

Autophagy has been identified as a cellular process of bulk degradation of cytoplasmic components and its persistent activation is critically involved in the renal damage induced by ureteral obstruction. However, the role and underlying mechanisms of autophagy in hyperuricemic nephropathy (HN) remain unknown. In the present study, we observed that inhibition of autophagy by 3-methyladenine (3-MA) abolished uric acid-induced differentiation of renal fibroblasts to myofibroblasts and activation of transforming growth factor-β1 (TGF-β1), epidermal growth factor receptor (EGFR), and Wnt signaling pathways in cultured renal interstitial fibroblasts. Treatment with 3-MA also abrogated the development of HN in vivo as evidenced by improving renal function, preserving renal tissue architecture, reducing the number of autophagic vacuoles, and decreasing microalbuminuria. Moreover, 3-MA was effective in attenuating renal deposition of extracellular matrix (ECM) proteins and expression of α-smooth muscle actin (α-SMA) and reducing renal epithelial cells arrested at the G2/M phase of cell cycle. Injury to the kidney resulted in increased expression of TGF-β1 and TGFβ receptor I, phosphorylation of Smad3 and TGF-β-activated kinase 1 (TAK1), and activation of multiple cell signaling pathways associated with renal fibrogenesis, including Wnt, Notch, EGFR, and nuclear factor-κB (NF-κB). 3-MA treatment remarkably inhibited all these responses. In addition, 3-MA effectively suppressed infiltration of macrophages and lymphocytes as well as release of multiple profibrogenic cytokines/chemokines in the injured kidney. Collectively, these findings indicate that hyperuricemia-induced autophagy is critically involved in the activation of renal fibroblasts and development of renal fibrosis and suggest that inhibition of autophagy may represent a potential therapeutic strategy for HN.

scholarly journals MALAT1 Modulates TGF-β1-Induced Endothelial-to-Mesenchymal Transition through Downregulation of miR-145

2017 ◽  
Vol 42 (1) ◽  
pp. 357-372 ◽  
Author(s):  
Yin Xiang ◽  
Yachen Zhang ◽  
Yong Tang ◽  
Qianhui Li
Keyword(s):  
Target Genes ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Neointimal Hyperplasia ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition ◽  
Tgf Β1

Background/Aims: Endothelial-to-mesenchymal transition (EndMT) plays significant roles under various pathological conditions including cardiovascular diseases, fibrosis, and cancer. EndMT of endothelial progenitor cells (EPCs) contributes to neointimal hyperplasia following cell therapy Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) that promotes metastasis and cancer. MicroRNA-145 (miR-145) is a tumor suppressor that has been reported to inhibit SMAD3-mediated epithelial-to-mesenchymal transition (EMT) of cancer cells. In the present study, we investigated the role of MALAT1 and miR-145 in EndMT of human circulating EPCs induced by transforming growth factor beta1 (TGF-β1). Methods: Human circulating EPCs were isolated and characterized by fluorescence-activated cell sorting (FACS). Expression levels of EndMT markers were assessed by qRT-PCR and western blotting. Alpha-smooth muscle actin (α-SMA) expression was measured by cell immunofluorescence staining. The regulatory relationship between MALAT1 and miR-145 and its target genes, TGFBR2 (TGFβ receptortype II) and SMAD3 (mothers against decapentaplegic homolog 3) was analyzed using the luciferase reporter assay. Results: We found that EndMT of EPCs induced by TGF-β1 is accompanied by increased MALAT1 expression and decreased miR-145 expression, and MALAT1 and miR-145 directly bind and reciprocally repress each other in these cells. Dual-Luciferase Reporter assay indicated that miR-145 inhibits TGF-β1-induced EndMT by directly targeting TGFBR2 and SMAD3. Conclusions: MALAT1 modulates TGF-β1-induced EndMT of EPCs through regulation of TGFBR2 and SMAD3 via miR-145. Thus, the MALAT1-miR-145-TGFBR2/SMAD3 signaling pathway plays a key role in TGF-β1-induced EndMT.

Inhibition of miR-182-5p attenuates pulmonary fibrosis via TGF-β/Smad pathway

2019 ◽  
Vol 39 (5) ◽  
pp. 683-695 ◽  
Author(s):  
Y Chen ◽  
Q Zhang ◽  
Y Zhou ◽  
Z Yang ◽  
M Tan
Keyword(s):  
Pulmonary Fibrosis ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Lung Fibroblasts ◽  
In Vitro Assays ◽  
Luciferase Reporter ◽  
High Morbidity ◽  
Human Embryonic Lung ◽  
Promising Therapeutic Approach ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with high morbidity and mortality. miR-182-5p is overexpressed in several fibrosis-related diseases but its effect in pulmonary fibrosis has not been reported yet. To investigate the function of miR-182-5p in pulmonary fibrosis, we established bleomycin (BLM)-induced fibrotic mice model and transforming growth factor-β1 (TGF-β1)-treated human embryonic lung fibroblasts model. In this study, miR-182-5p was highly expressed in pulmonary tissues of BLM-induced fibrotic mice. The content of hydroxyproline and TGF-β1 was decreased by downregulating the expression of miR-182-5p, indicating that fibrosis was alleviated in mice treated with Lentivirus-anti-miR-182-5p.Quantification of fibrosis-related proteins demonstrated that downregulation of miR-182-5p inhibited the expression of profibrotic proteins (fibronectin, α-smooth muscle actin, p-Smad2/p-Smad3) as well as enhanced the level of Smad7. In vitro assays validated that miR-182-5p was induced by TGF-β1 with the function of promoting fibrosis. In dual-luciferase reporter assay, Smad7 was demonstrated to be negatively regulated by miR-182-5p. Moreover, the effect of knocking down miR-182-5p on inhibiting fibrosis was achieved by upregulating the expression of Smad7. Therefore, miR-182-5p can be regarded as a biomarker of IPF and its inhibition may be a promising therapeutic approach in treating IPF.

A sensitive short-term evaluation of antifibrotic effects using newly established type I collagen reporter transgenic rats

2010 ◽  
Vol 299 (4) ◽  
pp. F792-F801 ◽  
Author(s):  
Hideki Terashima ◽  
Mikio Kato ◽  
Hiroaki Yasumo ◽  
Hiroshi Tsuchida ◽  
Makoto Mizuno ◽  
...  
Keyword(s):  
Renal Fibrosis ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Luciferase Activity ◽  
Smooth Muscle Actin ◽  
Luciferase Reporter ◽  
Type I ◽  
Hydroxyproline Content ◽  
Transgenic Rats ◽  
Short Period

Fibrosis is the final common pathway for various tissue lesions that lead to chronic progressive organ failure, and consequently effective antifibrotic drugs are strongly desired. However, there are few animal models in which it is possible to evaluate fibrosis sensitively in a short period of time. We therefore generated two transgenic rats harboring a firefly luciferase reporter gene under the control of the 5′-flanking region of rat α1(I) collagen (Col1a1-Luc Tg rats) and α2(I) collagen (Col1a2-Luc Tg rats). The luciferase activities of these transgenic rats were highly correlated with the hydroxyproline content in various organs. In unilateral ureteral obstruction (UUO), a well-characterized model of renal fibrosis, the luciferase activity in obstructed kidneys showed a significant increase after even 3 days of UUO, while the hydroxyproline content showed little increase. In addition, the renal hydroxyproline content had a higher correlation with the luciferase activity than α1(I) collagen mRNA level for over 2 wk after UUO. Although both an ANG II type 1 receptor blocker (ARB), olmesartan, and a transforming growth factor-β (TGF-β) type I receptor kinase (ALK5) inhibitor, SB-431542, inhibited renal luciferase activities in UUO, only SB-431542 inhibited luciferase activity induced by TGF-β1 in isolated glomeruli. Double immunostaining for luciferase and α-smooth muscle actin (α-SMA) revealed that some α-SMA-positive tubular epithelial cells and tubular interstitial cells produced type I collagen, which would lead to renal fibrosis. Thus collagen reporter transgenic rats would be very useful for the evaluation of antifibrotic effects and analysis of their mechanisms.

scholarly journals Simvastatin and ROCK Inhibitor Y-27632 Inhibit Myofibroblast Differentiation of Graves’ Ophthalmopathy-Derived Orbital Fibroblasts via RhoA-Mediated ERK and p38 Signaling Pathways

2021 ◽  
Vol 11 ◽  
Author(s):  
Yi-Hsuan Wei ◽  
Shu-Lang Liao ◽  
Sen-Hsu Wang ◽  
Chia-Chun Wang ◽  
Chang-Hao Yang
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Transforming Growth Factor Β ◽  
Mapk Signaling ◽  
Myofibroblast Differentiation ◽  
Rock Inhibitor ◽  
Graves Ophthalmopathy ◽  
Orbital Fibroblasts

Transforming growth factor-β (TGF-β)-induced differentiation of orbital fibroblasts into myofibroblasts is an important pathogenesis of Graves’ ophthalmopathy (GO) and leads to orbital tissue fibrosis. In the present study, we explored the antifibrotic effects of simvastatin and ROCK inhibitor Y-27632 in primary cultured GO orbital fibroblasts and tried to explain the molecular mechanisms behind these effects. Both simvastatin and Y-27632 inhibited TGF-β-induced α-smooth muscle actin (α-SMA) expression, which serves as a marker of fibrosis. The inhibitory effect of simvastatin on TGF-β-induced RhoA, ROCK1, and α-SMA expression could be reversed by geranylgeranyl pyrophosphate, an intermediate in the biosynthesis of cholesterol. This suggested that the mechanism of simvastatin-mediated antifibrotic effects may involve RhoA/ROCK signaling. Furthermore, simvastatin and Y-27632 suppressed TGF-β-induced phosphorylation of ERK and p38. The TGF-β-mediated α-SMA expression was suppressed by pharmacological inhibitors of p38 and ERK. These results suggested that simvastatin inhibits TGF-β-induced myofibroblast differentiation via suppression of the RhoA/ROCK/ERK and p38 MAPK signaling pathways. Thus, our study provides evidence that simvastatin and ROCK inhibitors may be potential therapeutic drugs for the prevention and treatment of orbital fibrosis in GO.

Down-regulation of hepatic nuclear factor 4α on expression of human hepatic stimulator substance via its action on the proximal promoter in HepG2 cells

2008 ◽  
Vol 415 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Duo Guo ◽  
Ling-yue Dong ◽  
Yuan Wu ◽  
Lin Yang ◽  
Wei An
Keyword(s):  
Hepg2 Cells ◽  
Promoter Activity ◽  
Transcriptional Control ◽  
Mrna Level ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Transcriptional Level ◽  
Nuclear Factor ◽  
Mobility Shift ◽  
Hepatic Stimulator Substance

hHSS (human hepatic stimulator substance) stimulates hepatocyte growth. To understand the mechanism controlling hHSS expression, we analysed the proximal promoter activity and identified two regulatory regions (−212/−192 and −152/−132) that were important for transcription in HepG2 cells. Using the luciferase reporter assay, gel-shift experiments and ChIP (chromatin immunoprecipitation), we found that the transcription factors HNF4α (hepatocyte nuclear factor 4α) and Sp1 (stimulating protein-1) were essential for hHSS promoter activity and could directly bind to regions −209/−204 and −152/−145 respectively. We also confirmed that activation and repression of hHSS transcription induced by Sp1 and HNF4α resulted from binding of these factors to these two cis-elements respectively. Overexpression of HNF4α led to a dramatic repression of the promoter activity and, in contrast, the activity was markedly elevated by overexpression of Sp1. Furthermore, overexpression of HNF4α1, one of the HNF4α isoforms, resulted in a dramatic suppression of the promoter activity. Moreover, repression of HNF4α expression by siRNA (small interfering RNA) remarkably enhanced the hHSS mRNA level. It has been reported previously that expression of HNF4α is functionally regulated by dexamethasone. To further confirm the transcriptional control of HNF4α on hHSS, we tested the effect of dexamethasone on hHSS transcription in HepG2 cells. In the present study we have demonstrated that the expression of the hHSS gene was down-regulated at the transcriptional level by dexamethasone in HepG2 cells. A deletion and decoy assay revealed that binding of HNF4α to nucleotides −209/−204 was responsible for the suppression of hHSS promoter activity by dexamethasone. Increases in the HNF4α-binding activity and expression were simultaneously observed in an electrophoretic mobility-shift assay and Western blot analysis. These results suggested that Sp1 activates hHSS basal expression, but HNF4α inhibits hHSS gene expression.

scholarly journals Endothelin-1 expression is strongly repressed by AU-rich elements in the 3′-untranslated region of the gene

2005 ◽  
Vol 387 (3) ◽  
pp. 763-772 ◽  
Author(s):  
Francisco M. REIMUNDE ◽  
Cristina CASTAÑARES ◽  
Mariano REDONDO-HORCAJO ◽  
Santiago LAMAS ◽  
Fernando RODRÍGUEZ-PASCUAL
Keyword(s):  
Untranslated Region ◽  
Transcriptional Control ◽  
Transforming Growth Factor ◽  
Mrna Level ◽  
Luciferase Reporter ◽  
Transcriptional Level ◽  
Regulation Of Expression ◽  
Control Of Gene Expression ◽  
Cytosolic Proteins ◽  
Endothelin 1

The regulation of the synthesis of the endothelial-derived vasoconstrictor ET-1 (endothelin-1) is a complex process that occurs mainly at the mRNA level. Transcription of the gene accounts for an important part of the regulation of expression, as already described for different modulators such as the cytokine TGF-β (transforming growth factor-β). However, very little is known about mechanisms governing ET-1 expression at the post-transcriptional level. The aim of the present study was to investigate the regulation of the ET-1 expression at this level. Since the 3′-UTR (3′-untranslated region) of mRNAs commonly contains genetic determinants for the post-transcriptional control of gene expression, we focused on the potential role of the 3′-UTR of ET-1 mRNA. Experiments performed with luciferase reporter constructs containing the 3′-UTR showed that this region exerts a potent destabilizing effect. Deletional analyses allowed us to locate this activity within a region at positions 924–1127. Some (but not all) of the AREs (AU-rich elements) present in this region were found to be essential for this mRNA-destabilizing activity. We also present evidence that cytosolic proteins from endothelial cells interact specifically with these RNA elements, and that a close correlation exists between the ability of the AREs to destabilize ET-1 mRNA and the binding of proteins to these elements. Our results are compatible with the existence of a strong repressional control of ET-1 expression mediated by destabilization of the mRNA exerted through the interaction of specific cytosolic proteins with AREs present in the 3′-UTR of the gene.

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