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1.  Organ-derived coatings on electrospun nanofibers as ex vivo microenvironments 
Biomaterials  2010;32(2):538-546.
Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterized by irreversible scarring. Collagen deposition, myofibroblast expansion, and the development of fibroblastic foci are the hallmark pathological events. The origin and mechanism of recruitment of myofibroblasts, the key cell contributing to these events, is unknown. We hypothesize that the fibrotic lung microenvironment causes differentiation of arriving bone marrow-derived cells into myofibroblasts. Therefore, a method of isolating the effects of fibrotic microenvironment components on various cell types was developed. Electrospun nanofibers were coated with lung extracts from fibrotic or nonfibrotic mice and used to determine effects on bone marrow cells from naïve mice. Varying moduli nanofibers were also employed to determine matrix stiffness effects on these cells. At structured time points, bone marrow cell morphology was recorded and changes in fibrotic gene expression determined by real-time PCR. Cells plated on extracts isolated from fibrotic murine lungs secreted larger amounts of extracellular matrix, adopted a fibroblastic morphology, and exhibited increased myofibroblast gene expression after 8 and 14 days; cells plated on extracts from nonfibrotic lungs did not. Similar results were observed when the nanofiber modulus was increased. This ex vivo system appears to recapitulate the three-dimensional fibrotic lung microenvironment.
doi:10.1016/j.biomaterials.2010.08.104
PMCID: PMC3671867  PMID: 20875916
Fibrosis; ECM; Electrospinning; Polycaprolactone; Fibroblast; Three-dimensional cell culture
2.  Transcription Factor ets-2 Plays an Important Role in the Pathogenesis of Pulmonary Fibrosis 
Ets-2 is a ubiquitous transcription factor activated after phosphorylation at threonine-72. Previous studies highlighted the importance of phosphorylated ets-2 in lung inflammation and extracellular matrix remodeling, two pathways involved in pulmonary fibrosis. We hypothesized that phosphorylated ets-2 played an important role in pulmonary fibrosis, and we sought to determine the role of ets-2 in its pathogenesis. We challenged ets-2 (A72/A72) transgenic mice (harboring a mutated form of ets-2 at phosphorylation site threonine-72) and ets-2 (wild-type/wild-type [WT/WT]) control mice with sequential intraperitoneal injections of bleomycin, followed by quantitative measurements of lung fibrosis and inflammation and primary cell in vitro assays. Concentrations of phosphorylated ets-2 were detected via the single and dual immunohistochemical staining of murine lungs and lung sections from patients with idiopathic pulmonary fibrosis. Ets-2 (A72/A72) mice were protected from bleomycin-induced pulmonary fibrosis, compared with ets-2 (WT/WT) mice. This protection was characterized by decreased lung pathological abnormalities and the fibrotic gene expression of Type I collagen, Type III collagen, α–smooth muscle actin, and connective tissue growth factor. Immunohistochemical staining of lung sections from bleomycin-treated ets-2 (WT/WT) mice and from patients with idiopathic pulmonary fibrosis demonstrated increased staining of phosphorylated ets-2 that colocalized with Type I collagen expression and to fibroblastic foci. Lastly, primary lung fibroblasts from ets-2 (A72/A72) mice exhibited decreased expression of Type I collagen in response to stimulation with TGF-β, compared with fibroblasts from ets-2 (WT/WT) mice. These data indicate the importance of phosphorylated ets-2 in the pathogenesis of pulmonary fibrosis through the expression of Type I collagen and (myo)fibroblast activation.
doi:10.1165/rcmb.2010-0490OC
PMCID: PMC3262682  PMID: 21562315
ets-2; Type I collagen; pulmonary fibrosis; bleomycin; fibroblast
3.  Thrombospondin-1 Contributes to Mortality in Murine Sepsis through Effects on Innate Immunity 
PLoS ONE  2011;6(5):e19654.
Background
Thrombospondin-1 (TSP-1) is involved in many biological processes, including immune and tissue injury response, but its role in sepsis is unknown. Cell surface expression of TSP-1 on platelets is increased in sepsis and could activate the anti-inflammatory cytokine transforming growth factor beta (TGFβ1) affecting outcome. Because of these observations we sought to determine the importance of TSP-1 in sepsis.
Methodology/Principal Findings
We performed studies on TSP-1 null and wild type (WT) C57BL/6J mice to determine the importance of TSP-1 in sepsis. We utilized the cecal ligation puncture (CLP) and intraperitoneal E.coli injection (IP E.coli) models of peritoneal sepsis. Additionally, bone-marrow-derived macrophages (BMMs) were used to determine phagocytic activity. TSP-1−/− animals experienced lower mortality than WT mice after CLP. Tissue and peritoneal lavage TGFβ1 levels were unchanged between animals of each genotype. In addition, there is no difference between the levels of major innate cytokines between the two groups of animals. PLF from WT mice contained a greater bacterial load than TSP-1−/− mice after CLP. The survival advantage for TSP-1−/− animals persisted when IP E.coli injections were performed. TSP-1−/− BMMs had increased phagocytic capacity compared to WT.
Conclusions
TSP-1 deficiency was protective in two murine models of peritoneal sepsis, independent of TGFβ1 activation. Our studies suggest TSP-1 expression is associated with decreased phagocytosis and possibly bacterial clearance, leading to increased peritoneal inflammation and mortality in WT mice. These data support the contention that TSP-1 should be more fully explored in the human condition.
doi:10.1371/journal.pone.0019654
PMCID: PMC3090410  PMID: 21573017

Results 1-3 (3)