Adenoviral Overexpression and Small Interfering RNA Suppression Demonstrate That Plasminogen Activator Inhibitor-1 Produces Elevated Collagen Accumulation in Normal and Keloid Fibroblasts

Tuan, Tai‐Lan; Hwu, P; Ho, Walter K.K.; Yiu, Peter; Chang, Richard N.; Wysocki, Annette B.; Benya, Paul D.

doi:10.2353/ajpath.2008.080272

Cited by 32 publications

(37 citation statements)

References 71 publications

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“…Such an inhibitory effect on collagen synthesis was also confirmed previously in an in vitro keloid model. 12 Despite the link between PAI-1 and apoptosis, 31 no significant changes were observed in our OC model. This could be explained by the low siRNA concentration used (250 nM).…”

Section: Discussionmentioning

confidence: 72%

“…Gene transfection using RNAi in human keloid cells either using cell culture or coculture was made possible with siRNA, 12 as well as in organotypic normal skin model. 30 However, there have been no studies to date investigating the applicability of RNAi to silence a target gene in a keloid OC model, to evaluate its efficiency as a potential antikeloid treatment in situ.…”

Section: Discussionmentioning

confidence: 99%

“…11 Knocking down PAI-1 using either short interfering RNA (siRNA) inhibited collagen synthesis in keloid fibroblasts. 12 The aim of this study was to validate EGCG and PAI-1 silencing in an actual human keloid OC model to generate optimal, clinically relevant preclinical evidence whether or not these antikeloid strategies deserve further clinical testing. EGCG treatment and PAI-1 knockdown in situ were compared with DEX as a positive control.…”

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confidence: 99%

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Ex vivo evaluation of antifibrotic compounds in skin scarring: EGCG and silencing of PAI-1 independently inhibit growth and induce keloid shrinkage

Syed

Bagabir

Paus

et al. 2013

Laboratory Investigation

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Keloid disease (KD) is a common fibroproliferative disorder of unknown etiopathogenesis. Its unique occurrence in human skin and lack of animal models pose challenges for KD research. The lack of a suitable model in KD and overreliance on cell culture has hampered the progress in developing new treatments. Therefore, we evaluated the effect of two promising candidate antifibrotic therapies: ( À )-epigallocatechin-3-gallate (EGCG) and plasminogen activator inhibitor-1 (PAI-1) silencing in a long-term human keloid organ culture (OC). Four millimeters of air-liquid interface (ALI) keloid explants on collagen gel matrix in serum-free medium (n ¼ 8 cases) were treated with different modalities (EGCG treatment; PAI-1 knockdown by short interfering RNA (siRNA) and application of dexamethasone (DEX) as control). Normal skin (n ¼ 6) was used as control (only for D0 keloid-untreated comparison). Besides routine histology and quantitative (immuno-) histomorphometry, the key phenotypic and growth parameters of KD were assessed. Results demonstrated that EGCG reduced keloid volume significantly (40% by week 4), increased apoptosis (Z40% from weeks 1 to 4), and decreased proliferation (r17% in week 2). EGCG induced epidermal shrinkage, reduced collagen-I and -III at mRNA and protein levels, depleted 98% of keloid-associated mast cells, and reduced the percentage of both cellularity and blood vessel count by week 4. Knockdown of PAI-1 significantly reduced keloid volume by 28% in week 4, respectively, and reduced collagen-I and -III at both mRNA and protein levels. As expected, DEX increased keloid apoptosis, decreased keloid proliferation, and collagen synthesis, but induced connective tissue growth factor overexpression. In conclusion, using keloid OC model, we provide the first functional evidence for testing candidate antifibrotic compounds in KD. We show that EGCG and PAI-1 silencing effectively inhibits growth and induces shrinkage of human keloid tissue in situ. Therefore, the application of EGCG, PAI-1 silencing, and other emerging compounds tested using this model may provide effective treatment and potentially aid in the prevention of recurrence of KD following surgery. Keloid disease (KD) is a benign hyperproliferative dermal disease of unknown etiopathogenesis with ill-defined treatment, 1 which is unique to humans. 2 KD can arise following an abnormal wound healing process in genetically susceptible individuals. 2 The hallmark of KD is excessive deposition of extracellular matrix (ECM) in the dermis. 3 The lack of an animal model that can truly mimic human KD in vivo condition imposes limitations when investigating functional activities of potential therapeutic agents in treating KD. 4,5 However, these models have failed to provide the essential components of skin tissue that occur in vivo, such as mature ECM, blood vessels, inflammatory cells, and intrinsic and extrinsic biochemical interactions. Therefore, the ultimate aim of this study was to determine the applicability of recent research findings in existing i...

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Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Ex vivo evaluation of antifibrotic compounds in skin scarring: EGCG and silencing of PAI-1 independently inhibit growth and induce keloid shrinkage

Syed

Bagabir

Paus

et al. 2013

Laboratory Investigation

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“…It is routine to compare patterns of gene expression in cultured cells at low passage number to minimize loss of an in vivo phenotype (Feghali and Wright, 1999; Smith et al , 2008; Tuan et al , 2008). It has been reported that simply culturing cells results in loss of a difference in α1β1 integrin collagen receptor expression between fibroblasts from keloids and normal skin (Szulgit et al , 2002).…”

Section: Discussionmentioning

confidence: 99%

Epigenetically Altered Wound Healing in Keloid Fibroblasts

Russell

Trupin

et al. 2010

Journal of Investigative Dermatology

148

152

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Keloids are benign dermal tumors that form during wound healing in genetically susceptible individuals. The mechanism(s) of keloid formation is unknown and there is no satisfactory treatment. We have reported differences between fibroblasts cultured from normal scars and keloids that include a pattern of glucocorticoid resistance and altered regulation of genes in several signaling pathways associated with fibrosis, including Wnt and IGF/IGF-binding protein 5 (IGFBP5). As previously reported for glucocorticoid resistance, decreased expression of the Wnt inhibitor secreted frizzled-related protein 1 (SFRP1), matrix metalloproteinase 3 (MMP3) and dermatopontin (DPT), and increased expression of IGFBP5 and jagged 1 (JAG1) are seen only in fibroblasts cultured from the keloid nodule. In vivo, decreased expression of SFRP1 and SFRP2 and increased expression of IGFBP5 are observed only in proliferative keloid tissue. There is no consistent difference in the replicative lifespan of normal and keloid fibroblasts, and the altered response to hydrocortisone (HC) and differential regulation of a subset of genes in standard culture medium are maintained throughout at least 80% of the culture lifetime. Preliminary studies using ChIP-chip analysis, Trichostatin A (TSA) and 5-aza-2′-deoxycytidine (5-aza-dC) further support an epigenetically altered program in keloid fibroblasts that includes an altered pattern of DNA methylation and histone acetylation.

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“…This altered ratio of uPA to PAI-1 causes less degradation of fibrin and other ECM proteins in keloid fibroblasts and thus contributes to dermal fibrogenesis (Tuan et al, 1996). Furthermore, while adenoviral-mediated overexpression of PAI-1 in normal and keloid skin fibroblasts causes significantly elevated levels of collagen accumulation, siRNA mediated depletion of cellular PAI-1 causes a reduction in the levels of collagen, suggesting PAI-1 controls the levels of collagen, an important profibrotic marker and contributor to hypertrophic scarring (Tuan et al, 2008). …”

Section: Pathobiology Of Tissue Fibrosismentioning

confidence: 99%

PAI‐1 in tissue fibrosis

Ghosh

Vaughan

2011

Journal Cellular Physiology

555

508

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1. Summary Fibrosis is defined as a fibroproliferative or abnormal fibroblast activation–related disease., Deregulation of wound healing leads to hyperactivation of fibroblasts and excessive accumulation of extracellular matrix (ECM) proteins in the wound area, the pathological manifestation of fibrosis. The accumulation of excessive levels of collagen in the extracellular matrix depends on two factors: an increased rate of collagen synthesis and or decreased rate of collagen degradation by cellular proteolytic activities. The urokinase-type/tissue-type plasminogen activator (uPA/tPA) and plasmin play significant roles in the cellular proteolytic degradation of ECM proteins and the maintenance of tissue homeostasis. The activities of uPA/tPA/plasmin and plasmin-dependent MMPs rely mostly on the activity of a potent inhibitor of uPA/tPA, plasminogen activator inhibitor-1 (PAI-1). Under normal physiologic conditions, PAI-1 controls the activities of uPA/tPA/plasmin/MMP proteolytic activities and thus maintains the tissue homeostasis. During wound healing, elevated levels of PAI-1 inhibit uPA/tPA/plasmin and plasmin-dependent MMP activities and thus help expedite wound healing. In contrast to this scenario, under pathologic conditions, excessive PAI-1 contributes to excessive accumulation of collagen and other ECM protein in the wound area and thus preserves scarring. While the level of PAI-1 is significantly elevated in fibrotic tissues, lack of PAI-1 protects different organs from fibrosis in response to injury-related profibrotic signals. Thus PAI-1 is implicated in the pathology of fibrosis in different organs including the heart, lung, kidney, liver and skin. Paradoxically, PAI-1 deficiency promotes spontaneous cardiac-selective fibrosis. In this review we discuss the significance of PAI-1 in the pathogenesis of fibrosis in multiple organs.

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Adenoviral Overexpression and Small Interfering RNA Suppression Demonstrate That Plasminogen Activator Inhibitor-1 Produces Elevated Collagen Accumulation in Normal and Keloid Fibroblasts

Cited by 32 publications

References 71 publications

Ex vivo evaluation of antifibrotic compounds in skin scarring: EGCG and silencing of PAI-1 independently inhibit growth and induce keloid shrinkage

Ex vivo evaluation of antifibrotic compounds in skin scarring: EGCG and silencing of PAI-1 independently inhibit growth and induce keloid shrinkage

Epigenetically Altered Wound Healing in Keloid Fibroblasts

PAI‐1 in tissue fibrosis

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