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Browsing by Subject "Transforming Growth Factor beta"
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Item Inhibition of CD1d-mediated antigen presentation by the transforming growth factor-β/Smad signalling pathway(Wiley Blackwell (Blackwell Publishing), 2014-12) Bailey, Jennifer C.; Iyer, Abhirami K.; Renukaradhya, Gourapura J.; Lin, Yinling; Nguyen, Hoa; Brutkiewicz, Randy R.; Department of Microbiology and Immunology, IU School of MedicineCD1d-mediated lipid antigen presentation activates a subset of innate immune lymphocytes called invariant natural killer T (NKT) cells that, by virtue of their potent cytokine production, bridge the innate and adaptive immune systems. Transforming growth factor (TGF-β) is a known immune modulator that can activate the mitogen-activated protein kinase p38; we have previously shown that p38 is a negative regulator of CD1d-mediated antigen presentation. Several studies implicate a role for TGF-β in the activation of p38. Therefore, we hypothesized that TGF-β would impair antigen presentation by CD1d. Indeed, a dose-dependent decrease in CD1d-mediated antigen presentation and impairment of lipid antigen processing was observed in response to TGF-β treatment. However, it was found that this inhibition was not through p38 activation. Instead, Smads 2, 3 and 4, downstream elements of the TGF-β canonical signalling pathway, contributed to the observed effects. In marked contrast to that observed with CD1d, TGF-β was found to enhance MHC class II-mediated antigen presentation. Overall, these results suggest that the canonical TGF-β/Smad pathway negatively regulates an important arm of the host's innate immune responses - CD1d-mediated lipid antigen presentation to NKT cells.Item STAT6 and Furin Are Successive Triggers for the Production of TGF-β by T Cells(The American Association of Immunologists, Inc., 2018-11) Li, Yue; Liu, Weiren; Guan, Xiaqun; Truscott, Jamie; Creemers, John W.; Chen, Hung-Lin; Pesu, Marko; El Abiad, Rami G.; Karacay, Bahri; Urban, Joseph F.; Elliott, David E.; Kaplan, Mark H.; Blazar, Bruce R.; Ince, M. Nedim; Pediatrics, School of MedicineProduction of TGF-β by T cells is key to various aspects of immune homeostasis, with defects in this process causing or aggravating immune-mediated disorders. The molecular mechanisms that lead to TGF-β generation by T cells remain largely unknown. To address this issue, we take advantage of the fact that intestinal helminths stimulate Th2 cells besides triggering TGF-β generation by T lymphocytes and regulate immune-mediated disorders. We show that the Th2 cell-inducing transcription factor STAT6 is necessary and sufficient for the expression of TGF-β propeptide in T cells. STAT6 is also necessary for several helminth-triggered events in mice, such as TGF-β-dependent suppression of alloreactive inflammation in graft-versus-host disease. Besides STAT6, helminth-induced secretion of active TGF-β requires cleavage of propeptide by the endopeptidase furin. Thus, for the immune regulatory pathway necessary for TGF-β production by T cells, our results support a two-step model, composed of STAT6 and furin.Item TGF-β induces global changes in DNA methylation during the epithelial-to-mesenchymal transition in ovarian cancer cells(Informa UK (Taylor & Francis), 2014-11) Cardenas, Horacio; Vieth, Edyta; Lee, Jiyoon; Segar, Mathew; Liu, Yunlong; Nephew, Kenneth P.; Matei, Daniela; Department of Medicine, IU School of MedicineA key step in the process of metastasis is the epithelial-to-mesenchymal transition (EMT). We hypothesized that epigenetic mechanisms play a key role in EMT and to test this hypothesis we analyzed global and gene-specific changes in DNA methylation during TGF-β-induced EMT in ovarian cancer cells. Epigenetic profiling using the Infinium HumanMethylation450 BeadChip (HM450) revealed extensive (P < 0.01) methylation changes after TGF-β stimulation (468 and 390 CpG sites altered at 48 and 120 h post cytokine treatment, respectively). The majority of gene-specific TGF-β-induced methylation changes occurred in CpG islands located in or near promoters (193 and 494 genes hypermethylated at 48 and 120 h after TGF-β stimulation, respectively). Furthermore, methylation changes were sustained for the duration of TGF-β treatment and reversible after the cytokine removal. Pathway analysis of the hypermethylated loci identified functional networks strongly associated with EMT and cancer progression, including cellular movement, cell cycle, organ morphology, cellular development, and cell death and survival. Altered methylation and corresponding expression of specific genes during TGF-β-induced EMT included CDH1 (E-cadherin) and COL1A1 (collagen 1A1). Furthermore, TGF-β induced both expression and activity of DNA methyltransferases (DNMT) -1, -3A, and -3B, and treatment with the DNMT inhibitor SGI-110 prevented TGF-β-induced EMT. These results demonstrate that dynamic changes in the DNA methylome are implicated in TGF-β-induced EMT and metastasis. We suggest that targeting DNMTs may inhibit this process by reversing the EMT genes silenced by DNA methylation in cancer.Item The TGF-β Signaling Regulator PMEPA1 Suppresses Prostate Cancer Metastases to Bone(Elsevier, 2015-06-08) Fournier, Pierrick GJ; Juárez, Patricia; Jiang, Guanglong; Clines, Gregory A.; Niewolna, Maria; Kim, Hun Soo; Walton, Holly W.; Peng, C. Xiang Hong; Liu, Yunlong; Mohammad, Khalid S.; Wells, Clark D.; Chirgwin, John M.; Guise, Theresa A.; Department of Medicine, IU School of MedicineTransforming growth factor-β (TGF-β) regulates the expression of genes supporting breast cancer cells in bone, but little is known about prostate cancer bone metastases and TGF-β. Our study reveals that the TGFBR1 inhibitor SD208 effectively reduces prostate cancer bone metastases. TGF-β upregulates in prostate cancer cells a set of genes associated with cancer aggressiveness and bone metastases, and the most upregulated gene was PMEPA1. In patients, PMEPA1 expression decreased in metastatic prostate cancer and low Pmepa1 correlated with decreased metastasis-free survival. Only membrane-anchored isoforms of PMEPA1 interacted with R-SMADs and ubiquitin ligases, blocking TGF-β signaling independently of the proteasome. Interrupting this negative feedback loop by PMEPA1 knockdown increased prometastatic gene expression and bone metastases in a mouse prostate cancer model.Item Tgfβ-Smad and MAPK signaling mediate scleraxis and proteoglycan expression in heart valves(Elsevier, 2013-12) Barnette, Damien N.; Hulin, Alexia; Ahmed, A.S. Ishtiaq; Colige, Alain C.; Azhar, Mohammed; Lincoln, Joy; Department of Pediatrics, IU School of MedicineMature heart valves are complex structures consisting of three highly organized extracellular matrix layers primarily composed of collagens, proteoglycans and elastin. Collectively, these diverse matrix components provide all the necessary biomechanical properties for valve function throughout life. In contrast to healthy valves, myxomatous valve disease is the most common cause of mitral valve prolapse in the human population and is characterized by an abnormal abundance of proteoglycans within the valve tri-laminar structure. Despite the clinical significance, the etiology of this phenotype is not known. Scleraxis (Scx) is a basic-helix-loop-helix transcription factor that we previously showed to be required for establishing heart valve structure during remodeling stages of valvulogenesis. In this study, we report that remodeling heart valves from Scx null mice express decreased levels of proteoglycans, particularly chondroitin sulfate proteoglycans (CSPGs), while overexpression in embryonic avian valve precursor cells and adult porcine valve interstitial cells increases CSPGs. Using these systems we further identify that Scx is positively regulated by canonical Tgfβ2 signaling during this process and this is attenuated by MAPK activity. Finally, we show that Scx is increased in myxomatous valves from human patients and mouse models, and overexpression in human mitral valve interstitial cells modestly increases proteoglycan expression consistent with myxomatous mitral valve phenotypes. Together, these studies identify an important role for Scx in regulating proteoglycans in embryonic and mature valve cells and suggest that imbalanced regulation could influence myxomatous pathogenesis.