The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Gary R Grotendorst - One of the best experts on this subject based on the ideXlab platform.
-
involvement of ctgf in tgf β1 stimulation of myofibroblast differentiation and collagen matrix contraction in the presence of mechanical stress
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Qian Garrett, Gary R Grotendorst, Timothy D Blalock, Peng T. Khaw, Gregory S Schultz, Julie T DanielsAbstract:PURPOSE: This study was undertaken to investigate the role of connective tissue growth factor (CTGF) in fibroblast-to-myofibroblast differentiation and fibroblast-mediated collagen matrix contraction in the presence of mechanical stress. METHODS: An in vitro three-dimensional contraction model of human corneal-fibroblast-seeded collagen lattices (FSCLs) in the presence of mechanical stress generated by attaching the lattices to the culture well was used to measure FSCL contraction. FSCLs were treated with CTGF; TGF-Beta1; serum-free (SF) control medium; or TGF-Beta1 plus antisense oligodeoxynucleotides to CTGF; TGF-Beta1 plus scrambled-sequence oligodeoxynucleotide to CTGF; or TGF-Beta antibody. Expression of alpha-smooth muscle actin (alpha-SMA) by fibroblasts in FSCLs was detected by immunostaining and confocal microscopy, whereas ELISA was used for the fibroblasts cultured on plastic. The conditioned media were analyzed by ELISA for CTGF production. RESULTS: Exogenous CTGF stimulated significantly less collagen matrix contraction and myofibroblast differentiation than TGF-Beta1, but similar to that stimulated by SF. TGF-Beta1 stimulated fibroblasts to express CTGF. CTGF antisense oligodeoxynucleotide inhibited TGF-Beta1-stimulated myofibroblast differentiation and FSCL contraction. Exogenous CTGF circumvented the inhibitory effects of CTGF antisense on FSCL contraction. TGF-Beta antibody significantly inhibited FSCL contraction and myofibroblast differentiation under mechanical stress and SF control conditions. CONCLUSIONS: In the presence of mechanical stress, CTGF is necessary for TGF-Beta1-stimulation of myofibroblast differentiation and subsequent collagen matrix contraction, but CTGF alone is not sufficient to induce myofibroblast differentiation and collagen matrix contraction. Thus, TGF-Beta1 appears to regulate multiple genes that are essential for fibroblast-mediated contraction of stressed matrix, one of which is CTGF.
-
combinatorial signaling pathways determine fibroblast proliferation and myofibroblast differentiation
The FASEB Journal, 2004Co-Authors: Gary R Grotendorst, Hamed Rahmanie, Matthew R DuncanAbstract:Fibroblast proliferation, differentiation into myofibroblasts, and increased collagen synthesis are key events during both normal wound repair and fibrotic lesion formation. Here we report that these biological responses to TGF-Beta by fibroblasts are regulated via a CTGF-dependent pathway in concert with either EGF or IGF-2. Our studies indicate these responses to TGF-Beta are mutually exclusive, and cells that are proliferating do not express alpha-SMA or elevated levels of collagen synthesis. Cells expressing alpha-SMA do not exhibit DNA synthesis but do coexpress higher levels of types I and III collagen mRNA. Thus, fibroblast proliferation and differentiation are controlled by combinatorial signaling pathways involving not only components of the TGF-Beta/CTGF pathway, but also signaling events induced by EGF and IGF-2-activated receptors. Collectively, our studies indicate TGF-Beta functions as a classic embryonic inducer, initiating a cascade that is controlled by other factors in the cellular environment. We propose a model for this process with regard to wound repair and fibrotic lesion formation that is likely applicable to other instances of CTGF action during embryogenesis.
-
connective tissue growth factor mediates transforming growth factor β induced collagen synthesis down regulation by camp
The FASEB Journal, 1999Co-Authors: Matthew R Duncan, Ken S Frazier, Susan Abramson, Shawn Williams, Helene Klapper, Xinfan Huang, Gary R GrotendorstAbstract:Connective tissue growth factor (CTGF) is a cysteine-rich peptide synthesized and secreted by fibroblastic cells after activation with transforming growth factor beta (TGF-Beta) that acts as a downstream mediator of TGF-Beta-induced fibroblast proliferation. We performed in vitro and in vivo studies to determine whether CTGF is also essential for TGF-Beta-induced fibroblast collagen synthesis. In vitro studies with normal rat kidney (NRK) fibroblasts demonstrated CTGF potently induces collagen synthesis and transfection with an antisense CTGF gene blocked TGF-Beta stimulated collagen synthesis. Moreover, TGF-Beta-induced collagen synthesis in both NRK and human foreskin fibroblasts was effectively blocked with specific anti-CTGF antibodies and by suppressing TGF-Beta-induced CTGF gene expression by elevating intracellular cAMP levels with either membrane-permeable 8-Br-cAMP or an adenylyl cyclase activator, cholera toxin (CTX). cAMP also inhibited collagen synthesis induced by CTGF itself, in contrast to its previously reported lack of effect on CTGF-induced DNA synthesis. In animal assays, CTX injected intradermally in transgenic mice suppressed TGF-Beta activation of a human CTGF promoter/lacZ reporter transgene. Both 8-Br-cAMP and CTX blocked TGF-Beta-induced collagen deposition in a wound chamber model of fibrosis in rats. CTX also reduced dermal granulation tissue fibroblast population increases induced by TGF-Beta in neonatal mice, but not increases induced by CTGF or TGF-Beta combined with CTGF. Our data indicate that CTGF mediates TGF-Beta-induced fibroblast collagen synthesis and that in vivo blockade of CTGF synthesis or action reduces TGF-Beta-induced granulation tissue formation by inhibiting both collagen synthesis and fibroblast accumulation.
-
connective tissue growth factor mediates transforming growth factor β induced collagen synthesis down regulation by camp
The FASEB Journal, 1999Co-Authors: Matthew R Duncan, Ken S Frazier, Susan Abramson, Shawn Williams, Helene Klapper, Xinfan Huang, Gary R GrotendorstAbstract:Connective tissue growth factor (CTGF) is a cysteine-rich peptide synthesized and secreted by fibroblastic cells after activation with transforming growth factor beta (TGF-β) that acts as a downstream mediator of TGF-β-induced fibroblast proliferation. We performed in vitro and in vivo studies to determine whether CTGF is also essential for TGF-β-induced fibroblast collagen synthesis. In vitro studies with normal rat kidney (NRK) fibroblasts demonstrated CTGF potently induces collagen synthesis and transfection with an antisense CTGF gene blocked TGF-β stimulated collagen synthesis. Moreover, TGF-β-induced collagen synthesis in both NRK and human foreskin fibroblasts was effectively blocked with specific anti-CTGF antibodies and by suppressing TGF-β-induced CTGF gene expression by elevating intracellular cAMP levels with either membrane-permeable 8-Br-cAMP or an adenylyl cyclase activator, cholera toxin (CTX). cAMP also inhibited collagen synthesis induced by CTGF itself, in contrast to its previously rep...
-
a novel transforming growth factor beta response element controls the expression of the connective tissue growth factor gene
Cell Growth & Differentiation, 1996Co-Authors: Gary R Grotendorst, Hitoshi Okochi, Nobukazu HayashiAbstract:We reported previously that transforming growth factor beta (TGF-Beta) selectively induced high levels of connective tissue growth factor (CTGF) mRNA and protein in human skin fibroblasts. In this study, we investigated the molecular mechanism for TGF-Beta regulation of CTGF gene expression. Northern blot and run-on transcription assays indicate that TGF-Beta directly activates transcription of the CTGF gene. Fragments of the 5'flanking region of the human CTGF gene were linked to luciferase reporter constructs. TGF-Beta induced a 25-30 fold increase in luciferase activity in NIH/3T3 fibroblasts that had been transfected with this construct compared with nontreated cells after 24 h incubation. Other growth factors, such as platelet derived growth factor or fibroblast growth factor, caused only a 2-3-fold induction. This response to TGF-Beta occurred only in human skin fibroblasts, fetal bovine aortic smooth muscle cells, and NIH/3T3 fibroblasts but not in the epithelial cell lines tested. Analysis of deletion mutants indicated that an important TGF-Beta regulatory element is located between positions -162 and -128 of the CTGF promoter sequence. A fragment of the promoter containing this region conferred TGF-Beta induction to a SV40 enhanceriess promoter. Methylation interference and competition gel shift assays mapped a unique 13-nucleotide sequence delineating a novel TGF-Beta cis-regulatory element. Point mutations in this region result in a complete loss of the TGF-Beta induction, identifying this sequence as a new TGF-Beta response element.
Peter Lorenz - One of the best experts on this subject based on the ideXlab platform.
-
hypertrophic scar fibroblasts have increased connective tissue growth factor expression after transforming growth factor beta stimulation
Plastic and Reconstructive Surgery, 2005Co-Authors: Amy S Colwell, Michael T. Longaker, Toanthang Phan, Wuyi Kong, Peter LorenzAbstract:BACKGROUND Hypertrophic scars and keloids respond to dermal disruption with excessive collagen deposition and increased transforming growth factor (TFG)-beta expression. Connective tissue growth factor (CTGF) is a downstream mediator of TGF-Beta activity that is associated with scar and fibrosis. The authors hypothesize that there is increased expression of CTGF by hypertrophic scar and keloid fibroblasts in response to TGF-Beta stimulation. METHODS Primary fibroblasts were isolated in culture from human hypertrophic scar (n = 2), keloid (n = 2), and normal skin (n = 2). After 18 hours of serum starvation, the cells were stimulated with 10 ng/ml of TGF-Beta1, TGF-Beta2, and TGF-Beta3 for 24 hours. Quantitative real-time polymerase chain reaction was performed on extracted RNA samples to assay for CTGF mRNA expression. RESULTS Baseline CTGF expression was increased 20-fold in unstimulated hypertrophic scar fibroblasts and 15-fold in keloid fibroblasts compared with normal fibroblasts. CTGF expression increased greater than 150-fold when stimulated with TGF-Beta1 (p < 0.002) and greater than 100-fold when stimulated by TGF-Beta2 or TGF-Beta3 compared with normal fibroblasts (p < 0.02 and p < 0.002, respectively). CTGF expression was greatest after TGF-Beta1 stimulation in hypertrophic scar fibroblasts compared with TGF-Beta2 (p < 0.04) and TGF-Beta3 (p < 0.02). Keloid fibroblast CTGF expression also increased greater than 100-fold after stimulation with TGF-Beta1 (p = 0.16) and greater than 75-fold after addition of TGF-Beta2 and TGF-Beta3 (p = 0.06 and p = 0.22, respectively). CONCLUSIONS Hypertrophic scar fibroblasts have both intrinsic up-regulation of CTGF transcription and an exaggerated capacity for CTGF transcription in response to TGF-Beta stimulation. These data suggest that blockage of CTGF activity may reduce pathologic scar formation.
-
hypertrophic scar fibroblasts have increased connective tissue growth factor expression after transforming growth factor beta stimulation
Plastic and Reconstructive Surgery, 2005Co-Authors: Amy S Colwell, Michael T. Longaker, Wuyi Kong, T T Phan, Peter LorenzAbstract:BACKGROUND: Hypertrophic scars and keloids respond to dermal disruption with excessive collagen deposition and increased transforming growth factor (TFG)-beta expression. Connective tissue growth factor (CTGF) is a downstream mediator of TGF-Beta activity that is associated with scar and fibrosis. The authors hypothesize that there is increased expression of CTGF by hypertrophic scar and keloid fibroblasts in response to TGF-Beta stimulation. METHODS: Primary fibroblasts were isolated in culture from human hypertrophic scar (n = 2), keloid (n = 2), and normal skin (n = 2). After 18 hours of serum starvation, the cells were stimulated with 10 ng/ml of TGF-Beta1, TGF-Beta2, and TGF-Beta3 for 24 hours. Quantitative real-time polymerase chain reaction was performed on extracted RNA samples to assay for CTGF mRNA expression. RESULTS: Baseline CTGF expression was increased 20-fold in unstimulated hypertrophic scar fibroblasts and 15-fold in keloid fibroblasts compared with normal fibroblasts. CTGF expression increased greater than 150-fold when stimulated with TGF-Beta1 (p < 0.002) and greater than 100-fold when stimulated by TGF-Beta2 or TGF-Beta3 compared with normal fibroblasts (p < 0.02 and p < 0.002, respectively). CTGF expression was greatest after TGF-Beta1 stimulation in hypertrophic scar fibroblasts compared with TGF-Beta2 (p < 0.04) and TGF-Beta3 (p < 0.02). Keloid fibroblast CTGF expression also increased greater than 100-fold after stimulation with TGF-Beta1 (p = 0.16) and greater than 75-fold after addition of TGF-Beta2 and TGF-Beta3 (p = 0.06 and p = 0.22, respectively). CONCLUSIONS: Hypertrophic scar fibroblasts have both intrinsic up-regulation of CTGF transcription and an exaggerated capacity for CTGF transcription in response to TGF-Beta stimulation. These data suggest that blockage of CTGF activity may reduce pathologic scar formation.
Satosha Terada - One of the best experts on this subject based on the ideXlab platform.
-
evaluation of the effects of platelet rich plasma prp therapy involved in the healing of sports related soft tissue injuries
The Iowa orthopaedic journal, 2012Co-Authors: Kellie K Middleton, Victor Barro, Bart Muller, Satosha TeradaAbstract:Musculoskeletal injuries are the most common cause of severe long-term pain and physical disability, and affect hundreds of millions of people around the world. One of the most popular methods used to biologically enhance healing in the fields of orthopaedic surgery and sports medicine includes the use of autologous blood products, namely, platelet rich plasma (PRP). PRP is an autologous concentration of human platelets to supra-physiologic levels. At baseline levels, platelets function as a natural reservoir for growth factors including platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and insulin-like growth factor (IGF-I). PRP is commonly used in orthopaedic practice to augment healing in sports-related injuries of skeletal muscle, tendons, and ligaments. Despite its pervasive use, the clinical efficacy of PrP therapy and varying mechanisms of action have yet to be established. Basic science research has revealed that PRP exerts is effects through many downstream events secondary to release of growth factors and other bioactive factors from its alpha granules. These effects may vary depending on the location of injury and the concentration of important growth factors involved in various soft tissue healing responses. This review focuses on the effects of PrP and its associated bioactive factors as elucidated in basic science research. Current findings in PRP basic science research, which have shed light on its proposed mechanisms of action, have opened doors for future areas of PrP research.
-
evaluation of the effects of platelet rich plasma prp therapy involved in the healing of sports related soft tissue injuries
The Iowa orthopaedic journal, 2012Co-Authors: Kellie K Middleton, Victor Barro, Bart Muller, Satosha Terada, Freddie H FuAbstract:Musculoskeletal injuries are the most common cause of severe long-term pain and physical disability, and affect hundreds of millions of people around the world. One of the most popular methods used to biologically enhance healing in the fields of orthopaedic surgery and sports medicine includes the use of autologous blood products, namely, platelet rich plasma (PRP). PRP is an autologous concentration of human platelets to supra-physiologic levels. At baseline levels, platelets function as a natural reservoir for growth factors including platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and insulin-like growth factor (IGF-I). PRP is commonly used in orthopaedic practice to augment healing in sports-related injuries of skeletal muscle, tendons, and ligaments. Despite its pervasive use, the clinical efficacy of PrP therapy and varying mechanisms of action have yet to be established. Basic science research has revealed that PRP exerts is effects through many downstream events secondary to release of growth factors and other bioactive factors from its alpha granules. These effects may vary depending on the location of injury and the concentration of important growth factors involved in various soft tissue healing responses. This review focuses on the effects of PrP and its associated bioactive factors as elucidated in basic science research. Current findings in PRP basic science research, which have shed light on its proposed mechanisms of action, have opened doors for future areas of PrP research.
Amy S Colwell - One of the best experts on this subject based on the ideXlab platform.
-
hypertrophic scar fibroblasts have increased connective tissue growth factor expression after transforming growth factor beta stimulation
Plastic and Reconstructive Surgery, 2005Co-Authors: Amy S Colwell, Michael T. Longaker, Toanthang Phan, Wuyi Kong, Peter LorenzAbstract:BACKGROUND Hypertrophic scars and keloids respond to dermal disruption with excessive collagen deposition and increased transforming growth factor (TFG)-beta expression. Connective tissue growth factor (CTGF) is a downstream mediator of TGF-Beta activity that is associated with scar and fibrosis. The authors hypothesize that there is increased expression of CTGF by hypertrophic scar and keloid fibroblasts in response to TGF-Beta stimulation. METHODS Primary fibroblasts were isolated in culture from human hypertrophic scar (n = 2), keloid (n = 2), and normal skin (n = 2). After 18 hours of serum starvation, the cells were stimulated with 10 ng/ml of TGF-Beta1, TGF-Beta2, and TGF-Beta3 for 24 hours. Quantitative real-time polymerase chain reaction was performed on extracted RNA samples to assay for CTGF mRNA expression. RESULTS Baseline CTGF expression was increased 20-fold in unstimulated hypertrophic scar fibroblasts and 15-fold in keloid fibroblasts compared with normal fibroblasts. CTGF expression increased greater than 150-fold when stimulated with TGF-Beta1 (p < 0.002) and greater than 100-fold when stimulated by TGF-Beta2 or TGF-Beta3 compared with normal fibroblasts (p < 0.02 and p < 0.002, respectively). CTGF expression was greatest after TGF-Beta1 stimulation in hypertrophic scar fibroblasts compared with TGF-Beta2 (p < 0.04) and TGF-Beta3 (p < 0.02). Keloid fibroblast CTGF expression also increased greater than 100-fold after stimulation with TGF-Beta1 (p = 0.16) and greater than 75-fold after addition of TGF-Beta2 and TGF-Beta3 (p = 0.06 and p = 0.22, respectively). CONCLUSIONS Hypertrophic scar fibroblasts have both intrinsic up-regulation of CTGF transcription and an exaggerated capacity for CTGF transcription in response to TGF-Beta stimulation. These data suggest that blockage of CTGF activity may reduce pathologic scar formation.
-
hypertrophic scar fibroblasts have increased connective tissue growth factor expression after transforming growth factor beta stimulation
Plastic and Reconstructive Surgery, 2005Co-Authors: Amy S Colwell, Michael T. Longaker, Wuyi Kong, T T Phan, Peter LorenzAbstract:BACKGROUND: Hypertrophic scars and keloids respond to dermal disruption with excessive collagen deposition and increased transforming growth factor (TFG)-beta expression. Connective tissue growth factor (CTGF) is a downstream mediator of TGF-Beta activity that is associated with scar and fibrosis. The authors hypothesize that there is increased expression of CTGF by hypertrophic scar and keloid fibroblasts in response to TGF-Beta stimulation. METHODS: Primary fibroblasts were isolated in culture from human hypertrophic scar (n = 2), keloid (n = 2), and normal skin (n = 2). After 18 hours of serum starvation, the cells were stimulated with 10 ng/ml of TGF-Beta1, TGF-Beta2, and TGF-Beta3 for 24 hours. Quantitative real-time polymerase chain reaction was performed on extracted RNA samples to assay for CTGF mRNA expression. RESULTS: Baseline CTGF expression was increased 20-fold in unstimulated hypertrophic scar fibroblasts and 15-fold in keloid fibroblasts compared with normal fibroblasts. CTGF expression increased greater than 150-fold when stimulated with TGF-Beta1 (p < 0.002) and greater than 100-fold when stimulated by TGF-Beta2 or TGF-Beta3 compared with normal fibroblasts (p < 0.02 and p < 0.002, respectively). CTGF expression was greatest after TGF-Beta1 stimulation in hypertrophic scar fibroblasts compared with TGF-Beta2 (p < 0.04) and TGF-Beta3 (p < 0.02). Keloid fibroblast CTGF expression also increased greater than 100-fold after stimulation with TGF-Beta1 (p = 0.16) and greater than 75-fold after addition of TGF-Beta2 and TGF-Beta3 (p = 0.06 and p = 0.22, respectively). CONCLUSIONS: Hypertrophic scar fibroblasts have both intrinsic up-regulation of CTGF transcription and an exaggerated capacity for CTGF transcription in response to TGF-Beta stimulation. These data suggest that blockage of CTGF activity may reduce pathologic scar formation.
Kellie K Middleton - One of the best experts on this subject based on the ideXlab platform.
-
evaluation of the effects of platelet rich plasma prp therapy involved in the healing of sports related soft tissue injuries
The Iowa orthopaedic journal, 2012Co-Authors: Kellie K Middleton, Victor Barro, Bart Muller, Satosha TeradaAbstract:Musculoskeletal injuries are the most common cause of severe long-term pain and physical disability, and affect hundreds of millions of people around the world. One of the most popular methods used to biologically enhance healing in the fields of orthopaedic surgery and sports medicine includes the use of autologous blood products, namely, platelet rich plasma (PRP). PRP is an autologous concentration of human platelets to supra-physiologic levels. At baseline levels, platelets function as a natural reservoir for growth factors including platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and insulin-like growth factor (IGF-I). PRP is commonly used in orthopaedic practice to augment healing in sports-related injuries of skeletal muscle, tendons, and ligaments. Despite its pervasive use, the clinical efficacy of PrP therapy and varying mechanisms of action have yet to be established. Basic science research has revealed that PRP exerts is effects through many downstream events secondary to release of growth factors and other bioactive factors from its alpha granules. These effects may vary depending on the location of injury and the concentration of important growth factors involved in various soft tissue healing responses. This review focuses on the effects of PrP and its associated bioactive factors as elucidated in basic science research. Current findings in PRP basic science research, which have shed light on its proposed mechanisms of action, have opened doors for future areas of PrP research.
-
evaluation of the effects of platelet rich plasma prp therapy involved in the healing of sports related soft tissue injuries
The Iowa orthopaedic journal, 2012Co-Authors: Kellie K Middleton, Victor Barro, Bart Muller, Satosha Terada, Freddie H FuAbstract:Musculoskeletal injuries are the most common cause of severe long-term pain and physical disability, and affect hundreds of millions of people around the world. One of the most popular methods used to biologically enhance healing in the fields of orthopaedic surgery and sports medicine includes the use of autologous blood products, namely, platelet rich plasma (PRP). PRP is an autologous concentration of human platelets to supra-physiologic levels. At baseline levels, platelets function as a natural reservoir for growth factors including platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and insulin-like growth factor (IGF-I). PRP is commonly used in orthopaedic practice to augment healing in sports-related injuries of skeletal muscle, tendons, and ligaments. Despite its pervasive use, the clinical efficacy of PrP therapy and varying mechanisms of action have yet to be established. Basic science research has revealed that PRP exerts is effects through many downstream events secondary to release of growth factors and other bioactive factors from its alpha granules. These effects may vary depending on the location of injury and the concentration of important growth factors involved in various soft tissue healing responses. This review focuses on the effects of PrP and its associated bioactive factors as elucidated in basic science research. Current findings in PRP basic science research, which have shed light on its proposed mechanisms of action, have opened doors for future areas of PrP research.
