Matthew Nugent - Academia.edu (original) (raw)

Papers by Matthew Nugent

Research paper thumbnail of New Insights into the Inhibition of Human Neutrophil Elastase by Heparin †

Research paper thumbnail of A Computational Approach for Deciphering the Organization of Glycosaminoglycans

Research paper thumbnail of Heparan sulfate depletion within pulmonary fibroblasts: Implications for elastogenesis and repair

Journal of Cellular Physiology, 2002

We investigated the role of sulfated proteoglycans in regulating extracellular matrix (ECM) depos... more We investigated the role of sulfated proteoglycans in regulating extracellular matrix (ECM) deposition in pulmonary fibroblast cultures. Fibroblast cultures were subject to pharmacologic and enzymatic interventions to modify sulfated proteoglycan levels. Native and proteoglycan-depleted fibroblasts were treated with porcine pancreatic elastase at 2-4-day intervals and the elastase-mediated release of fibroblast growth factor 2 (FGF-2) and glycosaminoglycans was determined. Elastase treatment released significantly less FGF-2 and glycosaminoglycans (GAG) from PG-depleted fibroblasts with respect to native cells. Equilibrium ligand binding studies indicated that 125I FGF-2 binding at both cell surface receptor and heparan sulfate proteoglycan sites was reduced to different extents based on the method of proteoglycan depletion. Quantitation of elastin protein and message levels indicated that biological sulfation is required for the proper incorporation of tropoelastin into the extracellular matrix. These results suggest that sulfated proteoglycans play a central role in modulating pulmonary fibroblast extracellular matrix composition and are important mediators of elastolytic injury.

Research paper thumbnail of Basic Fibroblast Growth Factor Decreases Elastin Gene Transcription through an AP1/cAMP-response Element Hybrid Site in the Distal Promoter

Journal of Biological Chemistry, 1999

Research paper thumbnail of Elastase Mediates the Release of Growth Factors from Lung In Vivo

Uncontrolled elastase activity is involved in the development of several types of lung disease. P... more Uncontrolled elastase activity is involved in the development of several types of lung disease. Previous reports demonstrated that growth factors are liberated from pulmonary matrix storage sites by elastase; however, release of these entities in vivo is not well defined. In the present study, we investigated the release of fibro- blast growth factor-2 (FGF-2) and transforming growth factor- (TGF-), after

Research paper thumbnail of Transcriptional regulation of pulmonary elastin gene expression in elastase-induced injury

American Journal of Physiology - Lung Cellular and Molecular Physiology, 2003

Previously we have shown that treatment of confluent, pulmonary fibroblast cultures with elastase... more Previously we have shown that treatment of confluent, pulmonary fibroblast cultures with elastase results in upregulation of elastin mRNA and protein levels. In the present study we focused on determining the level at which elastin expression is upregulated after elastase exposure. We examined as models for this investigation elastin gene expression in primary pulmonary fibroblast cells during the transition from subconfluent to confluent cultures and in confluent, matrix-laden cultures treated briefly with elastase. In addition, we extended our studies to mice that were given an intratracheal dose of elastase; the effects on lung elastin mRNA and elastin promoter activity levels were measured and compared with results from in vitro cell models. The results demonstrate that upregulation of elastin gene expression during the transition of subconfluent to confluent cultures and after elastase injury is associated with an increase in the level of transcription both in vitro and in vivo. Furthermore, intratracheal administration of elastase to transgenic mice illustrates that the increased levels of elastin mRNA are accompanied by increased activity of the elastin gene promoter in cells spatially positioned near major sites of tissue injury.

Research paper thumbnail of Development of a new in vivo model of pulmonary emphysema

Research paper thumbnail of Regulation of heparan sulfate proteoglycan nuclear localization by fibronectin

Heparan sulfate proteoglycans (HSPG) regulate multiple cellular processes and mediate the cellula... more Heparan sulfate proteoglycans (HSPG) regulate multiple cellular processes and mediate the cellular uptake of numerous molecules. While heparan sulphate glycosaminoglycan chains are known to modulate receptor binding of several heparin-binding proteins, here we show that distinct extracellular matrices direct HSPG to the nucleus. We analyzed HSPG localization in primary corneal fibroblasts, cultured on fibronectin or collagen type I matrices, using

Research paper thumbnail of Dynamics of enzymatic digestion of elastic fibers and networks under tension

Proceedings of the National Academy of Sciences

We study the enzymatic degradation of an elastic fiber under tension using an anisotropic random-... more We study the enzymatic degradation of an elastic fiber under tension using an anisotropic random-walk model coupled with binding-unbinding reactions that weaken the fiber. The fiber is represented by a chain of elastic springs in series along which enzyme molecules can diffuse. Numerical simulations show that the fiber stiffness decreases exponentially with two distinct regimes. The time constant of the first regime decreases with increasing tension. Using a mean field calculation, we partition the time constant into geometrical, chemical and externally controllable factors, which is corroborated by the simulations. We incorporate the fiber model into a multiscale network model of the extracellular matrix and find that network effects do not mask the exponential decay of stiffness at the fiber level. To test these predictions, we measure the force relaxation of elastin sheets stretched to 20% uniaxial strain in the presence of elastase. The decay of force is exponential and the time...

Research paper thumbnail of Distribution Of Fragments During Elastase Digestion Of Elastin Fibers

Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYS... more Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYSIOLOGY OF EMPHYSEMA (Street Level), Colorado Convention Center Distribution Of Fragments During Elastase Digestion Of Elastin Fibers ...

Research paper thumbnail of A novel device to stretch multiple tissue samples with variable patterns: Application for mRNA regulation in tissue-engineered constructs

A broad range of cells are subjected to irregular time varying mechanical stimuli within the body... more A broad range of cells are subjected to irregular time varying mechanical stimuli within the body, particularly in the respiratory and circulatory systems. Mechanical stretch is an important factor in determining cell function; however, the effects of variable stretch remain unexplored. In order to investigate the effects of variable stretch, we designed, built and tested a uniaxial stretching device that can stretch three-dimensional tissue constructs while varying the strain amplitude from cycle to cycle. The device is the first to apply variable stretching signals to cells in tissues or three dimensional tissue constructs. Following device validation, we applied 20% strain to Gelfoam samples seeded with neonatal rat lung fibroblasts with different levels of variability (0%, 25%, 50% and 75%). RT-PCR was then performed to measure the effects of variable stretch on key molecules involved in cell-matrix interactions including: collagen 1α, lysyl oxidase, α-actin, β1 integrin, β3 int...

Research paper thumbnail of Oligosaccharide substrate preferences of human extracellular sulfatase Sulf2 using liquid chromatography-mass spectrometry based glycomics approaches

PloS one, 2014

Sulfs are extracellular endosulfatases that selectively remove the 6-O-sulfate groups from cell s... more Sulfs are extracellular endosulfatases that selectively remove the 6-O-sulfate groups from cell surface heparan sulfate (HS) chain. By altering the sulfation at these particular sites, Sulfs function to remodel HS chains. As a result of the remodeling activity, HSulf2 regulates a multitude of cell-signaling events that depend on interactions between proteins and HS. Previous efforts to characterize the substrate specificity of human Sulfs (HSulfs) focused on the analysis of HS disaccharides and synthetic repeating units. In this study, we characterized the substrate preferences of human HSulf2 using HS oligosaccharides with various lengths and sulfation degrees from several naturally occurring HS sources by applying liquid chromatography mass spectrometry based glycomics methods. The results showed that HSulf2 preferentially digests highly sulfated HS oligosaccharides with zero acetyl groups and this preference is length dependent. In terms of length of oligosaccharides, HSulf2 dige...

Research paper thumbnail of Distribution Of Fragments During Elastase Digestion Of Elastin Fibers

D28. PATHOPHYSIOLOGY OF EMPHYSEMA, 2011

Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYS... more Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYSIOLOGY OF EMPHYSEMA (Street Level), Colorado Convention Center Distribution Of Fragments During Elastase Digestion Of Elastin Fibers ...

Research paper thumbnail of Heparin-binding EGF-like growth factor regulates elastin and FGF-2 expression in pulmonary fibroblasts

American Journal of Physiology - Lung Cellular and Molecular Physiology, 2003

Research paper thumbnail of Heparan sulfates expressed in the distal lung are required for Fgf10 binding to the epithelium and for airway branching

American journal of physiology. Lung cellular and molecular physiology, 2003

Fibroblast growth factor (Fgf) 10 is a critical regulator of bud formation during lung morphogene... more Fibroblast growth factor (Fgf) 10 is a critical regulator of bud formation during lung morphogenesis. fgf10 is expressed in distal lung mesenchyme at sites of prospective budding from the earliest developmental stages and signals through its epithelial receptor Fgfr2b. Experiments in intact lung organ cultures demonstrate that Fgf10 is a chemotactic factor for distal, but not for proximal, epithelium. This differential response suggests the involvement of an additional mechanism regulating Fgf10-Fgfr2b interactions, because Fgfr2b is uniformly expressed throughout the respiratory tract. Here we use an immunohistochemistry-based binding assay to show that O-sulfated heparan sulfates (HS) are critical for Fgf10 binding to the distal epithelium. We show that altering endogenous gradients of HS sulfation with sodium chlorate or over-O-sulfated synthetic heparin in lung organ cultures dramatically decreases Fgf10 binding. Moreover, we show that under these conditions epithelial binding i...

Research paper thumbnail of A liquid chromatography-mass spectrometry-based approach to characterize the substrate specificity of mammalian heparanase

The Journal of biological chemistry, Jan 5, 2014

Extracellular heparanase activity releases growth factors and angiogenic factors from heparan sul... more Extracellular heparanase activity releases growth factors and angiogenic factors from heparan sulfate (HS) storage sites and alters the integrity of the extracellular matrix. These activities lead to a loss of normal cell matrix adherent junctions and correlate with invasive cellular phenotypes. Elevated expression of heparanase is associated with several human cancers and with vascular remodeling. Heparanase cleaves only a limited fraction of glucuronidic linkages in HS. There have been few investigations of the functional consequences of heparanase activity, largely due to the heterogeneity and complexity of HS. Here, we report a liquid chromatography-mass spectrometry (LC-MS)-based approach to profile the terminal structures created by heparanase digestion and reconstruct the heparanase cleavage sites from the products. Using this method, we demonstrate that heparanase cleaves at the non-reducing side of highly sulfated HS domains, exposing cryptic growth factor binding sites. Th...

Research paper thumbnail of Design Of A Multi-Well Tissue Stretching Device Tested Using Respiratory Tissue-Engineered Constructs

C27. GENETIC PROGRAMS DRIVING LUNG DEVELOPMENT AND REGENERATION, 2011

Research paper thumbnail of A novel device to stretch multiple tissue samples with variable patterns: Application for mRNA regulation in tissue-engineered constructs

Research paper thumbnail of Docking Server for the Identification of Heparin Binding Sites on Proteins

Journal of Chemical Information and Modeling, 2014

Research paper thumbnail of Ascorbate enhances elastin synthesis in 3D tissue-engineered pulmonary fibroblasts constructs

Tissue and Cell, 2013

Extracellular matrix remodeling is a continuous process that is critical to maintaining tissue ho... more Extracellular matrix remodeling is a continuous process that is critical to maintaining tissue homeostasis, and alterations in this process have been implicated in chronic diseases such as atherosclerosis, lung fibrosis, and emphysema. Collagen and elastin are subject to ascorbate-dependent hydroxylation. While this post-translational modification in collagen is critical for function, the role of hydroxylation of elastin is not well understood. A number of studies have indicated that ascorbate leads to reduced elastin synthesis. However, these studies were limited to analysis of cells grown under traditional 2D tissue culture conditions. To investigate this process we evaluated elastin and collagen synthesis in primary rat neonatal pulmonary fibroblasts in response to ascorbate treatment in traditional 2D culture and within 3D cross-linked gelatin matrices (Gelfoam). We observed little change in elastin or collagen biosynthesis in standard 2D cultures treated with ascorbate, yet observed a dramatic increase in elastin protein and mRNA levels in response to ascorbate in 3D cell-Gelfoam constructs. These data suggest that the cell-ECM architecture dictates pulmonary cell response to ascorbate, and that approaches aimed toward stimulating ECM repair or engineering functional cell-derived matrices should consider all aspects of the cellular environment.

Research paper thumbnail of New Insights into the Inhibition of Human Neutrophil Elastase by Heparin †

Research paper thumbnail of A Computational Approach for Deciphering the Organization of Glycosaminoglycans

Research paper thumbnail of Heparan sulfate depletion within pulmonary fibroblasts: Implications for elastogenesis and repair

Journal of Cellular Physiology, 2002

We investigated the role of sulfated proteoglycans in regulating extracellular matrix (ECM) depos... more We investigated the role of sulfated proteoglycans in regulating extracellular matrix (ECM) deposition in pulmonary fibroblast cultures. Fibroblast cultures were subject to pharmacologic and enzymatic interventions to modify sulfated proteoglycan levels. Native and proteoglycan-depleted fibroblasts were treated with porcine pancreatic elastase at 2-4-day intervals and the elastase-mediated release of fibroblast growth factor 2 (FGF-2) and glycosaminoglycans was determined. Elastase treatment released significantly less FGF-2 and glycosaminoglycans (GAG) from PG-depleted fibroblasts with respect to native cells. Equilibrium ligand binding studies indicated that 125I FGF-2 binding at both cell surface receptor and heparan sulfate proteoglycan sites was reduced to different extents based on the method of proteoglycan depletion. Quantitation of elastin protein and message levels indicated that biological sulfation is required for the proper incorporation of tropoelastin into the extracellular matrix. These results suggest that sulfated proteoglycans play a central role in modulating pulmonary fibroblast extracellular matrix composition and are important mediators of elastolytic injury.

Research paper thumbnail of Basic Fibroblast Growth Factor Decreases Elastin Gene Transcription through an AP1/cAMP-response Element Hybrid Site in the Distal Promoter

Journal of Biological Chemistry, 1999

Research paper thumbnail of Elastase Mediates the Release of Growth Factors from Lung In Vivo

Uncontrolled elastase activity is involved in the development of several types of lung disease. P... more Uncontrolled elastase activity is involved in the development of several types of lung disease. Previous reports demonstrated that growth factors are liberated from pulmonary matrix storage sites by elastase; however, release of these entities in vivo is not well defined. In the present study, we investigated the release of fibro- blast growth factor-2 (FGF-2) and transforming growth factor- (TGF-), after

Research paper thumbnail of Transcriptional regulation of pulmonary elastin gene expression in elastase-induced injury

American Journal of Physiology - Lung Cellular and Molecular Physiology, 2003

Previously we have shown that treatment of confluent, pulmonary fibroblast cultures with elastase... more Previously we have shown that treatment of confluent, pulmonary fibroblast cultures with elastase results in upregulation of elastin mRNA and protein levels. In the present study we focused on determining the level at which elastin expression is upregulated after elastase exposure. We examined as models for this investigation elastin gene expression in primary pulmonary fibroblast cells during the transition from subconfluent to confluent cultures and in confluent, matrix-laden cultures treated briefly with elastase. In addition, we extended our studies to mice that were given an intratracheal dose of elastase; the effects on lung elastin mRNA and elastin promoter activity levels were measured and compared with results from in vitro cell models. The results demonstrate that upregulation of elastin gene expression during the transition of subconfluent to confluent cultures and after elastase injury is associated with an increase in the level of transcription both in vitro and in vivo. Furthermore, intratracheal administration of elastase to transgenic mice illustrates that the increased levels of elastin mRNA are accompanied by increased activity of the elastin gene promoter in cells spatially positioned near major sites of tissue injury.

Research paper thumbnail of Development of a new in vivo model of pulmonary emphysema

Research paper thumbnail of Regulation of heparan sulfate proteoglycan nuclear localization by fibronectin

Heparan sulfate proteoglycans (HSPG) regulate multiple cellular processes and mediate the cellula... more Heparan sulfate proteoglycans (HSPG) regulate multiple cellular processes and mediate the cellular uptake of numerous molecules. While heparan sulphate glycosaminoglycan chains are known to modulate receptor binding of several heparin-binding proteins, here we show that distinct extracellular matrices direct HSPG to the nucleus. We analyzed HSPG localization in primary corneal fibroblasts, cultured on fibronectin or collagen type I matrices, using

Research paper thumbnail of Dynamics of enzymatic digestion of elastic fibers and networks under tension

Proceedings of the National Academy of Sciences

We study the enzymatic degradation of an elastic fiber under tension using an anisotropic random-... more We study the enzymatic degradation of an elastic fiber under tension using an anisotropic random-walk model coupled with binding-unbinding reactions that weaken the fiber. The fiber is represented by a chain of elastic springs in series along which enzyme molecules can diffuse. Numerical simulations show that the fiber stiffness decreases exponentially with two distinct regimes. The time constant of the first regime decreases with increasing tension. Using a mean field calculation, we partition the time constant into geometrical, chemical and externally controllable factors, which is corroborated by the simulations. We incorporate the fiber model into a multiscale network model of the extracellular matrix and find that network effects do not mask the exponential decay of stiffness at the fiber level. To test these predictions, we measure the force relaxation of elastin sheets stretched to 20% uniaxial strain in the presence of elastase. The decay of force is exponential and the time...

Research paper thumbnail of Distribution Of Fragments During Elastase Digestion Of Elastin Fibers

Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYS... more Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYSIOLOGY OF EMPHYSEMA (Street Level), Colorado Convention Center Distribution Of Fragments During Elastase Digestion Of Elastin Fibers ...

Research paper thumbnail of A novel device to stretch multiple tissue samples with variable patterns: Application for mRNA regulation in tissue-engineered constructs

A broad range of cells are subjected to irregular time varying mechanical stimuli within the body... more A broad range of cells are subjected to irregular time varying mechanical stimuli within the body, particularly in the respiratory and circulatory systems. Mechanical stretch is an important factor in determining cell function; however, the effects of variable stretch remain unexplored. In order to investigate the effects of variable stretch, we designed, built and tested a uniaxial stretching device that can stretch three-dimensional tissue constructs while varying the strain amplitude from cycle to cycle. The device is the first to apply variable stretching signals to cells in tissues or three dimensional tissue constructs. Following device validation, we applied 20% strain to Gelfoam samples seeded with neonatal rat lung fibroblasts with different levels of variability (0%, 25%, 50% and 75%). RT-PCR was then performed to measure the effects of variable stretch on key molecules involved in cell-matrix interactions including: collagen 1α, lysyl oxidase, α-actin, β1 integrin, β3 int...

Research paper thumbnail of Oligosaccharide substrate preferences of human extracellular sulfatase Sulf2 using liquid chromatography-mass spectrometry based glycomics approaches

PloS one, 2014

Sulfs are extracellular endosulfatases that selectively remove the 6-O-sulfate groups from cell s... more Sulfs are extracellular endosulfatases that selectively remove the 6-O-sulfate groups from cell surface heparan sulfate (HS) chain. By altering the sulfation at these particular sites, Sulfs function to remodel HS chains. As a result of the remodeling activity, HSulf2 regulates a multitude of cell-signaling events that depend on interactions between proteins and HS. Previous efforts to characterize the substrate specificity of human Sulfs (HSulfs) focused on the analysis of HS disaccharides and synthetic repeating units. In this study, we characterized the substrate preferences of human HSulf2 using HS oligosaccharides with various lengths and sulfation degrees from several naturally occurring HS sources by applying liquid chromatography mass spectrometry based glycomics methods. The results showed that HSulf2 preferentially digests highly sulfated HS oligosaccharides with zero acetyl groups and this preference is length dependent. In terms of length of oligosaccharides, HSulf2 dige...

Research paper thumbnail of Distribution Of Fragments During Elastase Digestion Of Elastin Fibers

D28. PATHOPHYSIOLOGY OF EMPHYSEMA, 2011

Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYS... more Page 1. / Poster Discussion Session / Wednesday, May 18/8:15 AM-10:45 AM / Room 601 D28 PATHOPHYSIOLOGY OF EMPHYSEMA (Street Level), Colorado Convention Center Distribution Of Fragments During Elastase Digestion Of Elastin Fibers ...

Research paper thumbnail of Heparin-binding EGF-like growth factor regulates elastin and FGF-2 expression in pulmonary fibroblasts

American Journal of Physiology - Lung Cellular and Molecular Physiology, 2003

Research paper thumbnail of Heparan sulfates expressed in the distal lung are required for Fgf10 binding to the epithelium and for airway branching

American journal of physiology. Lung cellular and molecular physiology, 2003

Fibroblast growth factor (Fgf) 10 is a critical regulator of bud formation during lung morphogene... more Fibroblast growth factor (Fgf) 10 is a critical regulator of bud formation during lung morphogenesis. fgf10 is expressed in distal lung mesenchyme at sites of prospective budding from the earliest developmental stages and signals through its epithelial receptor Fgfr2b. Experiments in intact lung organ cultures demonstrate that Fgf10 is a chemotactic factor for distal, but not for proximal, epithelium. This differential response suggests the involvement of an additional mechanism regulating Fgf10-Fgfr2b interactions, because Fgfr2b is uniformly expressed throughout the respiratory tract. Here we use an immunohistochemistry-based binding assay to show that O-sulfated heparan sulfates (HS) are critical for Fgf10 binding to the distal epithelium. We show that altering endogenous gradients of HS sulfation with sodium chlorate or over-O-sulfated synthetic heparin in lung organ cultures dramatically decreases Fgf10 binding. Moreover, we show that under these conditions epithelial binding i...

Research paper thumbnail of A liquid chromatography-mass spectrometry-based approach to characterize the substrate specificity of mammalian heparanase

The Journal of biological chemistry, Jan 5, 2014

Extracellular heparanase activity releases growth factors and angiogenic factors from heparan sul... more Extracellular heparanase activity releases growth factors and angiogenic factors from heparan sulfate (HS) storage sites and alters the integrity of the extracellular matrix. These activities lead to a loss of normal cell matrix adherent junctions and correlate with invasive cellular phenotypes. Elevated expression of heparanase is associated with several human cancers and with vascular remodeling. Heparanase cleaves only a limited fraction of glucuronidic linkages in HS. There have been few investigations of the functional consequences of heparanase activity, largely due to the heterogeneity and complexity of HS. Here, we report a liquid chromatography-mass spectrometry (LC-MS)-based approach to profile the terminal structures created by heparanase digestion and reconstruct the heparanase cleavage sites from the products. Using this method, we demonstrate that heparanase cleaves at the non-reducing side of highly sulfated HS domains, exposing cryptic growth factor binding sites. Th...

Research paper thumbnail of Design Of A Multi-Well Tissue Stretching Device Tested Using Respiratory Tissue-Engineered Constructs

C27. GENETIC PROGRAMS DRIVING LUNG DEVELOPMENT AND REGENERATION, 2011

Research paper thumbnail of A novel device to stretch multiple tissue samples with variable patterns: Application for mRNA regulation in tissue-engineered constructs

Research paper thumbnail of Docking Server for the Identification of Heparin Binding Sites on Proteins

Journal of Chemical Information and Modeling, 2014

Research paper thumbnail of Ascorbate enhances elastin synthesis in 3D tissue-engineered pulmonary fibroblasts constructs

Tissue and Cell, 2013

Extracellular matrix remodeling is a continuous process that is critical to maintaining tissue ho... more Extracellular matrix remodeling is a continuous process that is critical to maintaining tissue homeostasis, and alterations in this process have been implicated in chronic diseases such as atherosclerosis, lung fibrosis, and emphysema. Collagen and elastin are subject to ascorbate-dependent hydroxylation. While this post-translational modification in collagen is critical for function, the role of hydroxylation of elastin is not well understood. A number of studies have indicated that ascorbate leads to reduced elastin synthesis. However, these studies were limited to analysis of cells grown under traditional 2D tissue culture conditions. To investigate this process we evaluated elastin and collagen synthesis in primary rat neonatal pulmonary fibroblasts in response to ascorbate treatment in traditional 2D culture and within 3D cross-linked gelatin matrices (Gelfoam). We observed little change in elastin or collagen biosynthesis in standard 2D cultures treated with ascorbate, yet observed a dramatic increase in elastin protein and mRNA levels in response to ascorbate in 3D cell-Gelfoam constructs. These data suggest that the cell-ECM architecture dictates pulmonary cell response to ascorbate, and that approaches aimed toward stimulating ECM repair or engineering functional cell-derived matrices should consider all aspects of the cellular environment.