Agnes Banfalvi
University of Southern California
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Publication
Featured researches published by Agnes Banfalvi.
Journal of Clinical Investigation | 2011
Min Li; Manda S. Krishnaveni; Changgong Li; Beiyun Zhou; Yiming Xing; Agnes Banfalvi; Aimin Li; Vincent Lombardi; Omid Akbari; Zea Borok; Parviz Minoo
Idiopathic pulmonary fibrosis (IPF) is a chronic fibroproliferative pulmonary disorder for which there are currently no treatments. Although the etiology of IPF is unknown, dysregulated TGF-β signaling has been implicated in its pathogenesis. Recent studies also suggest a central role for abnormal epithelial repair. In this study, we sought to elucidate the function of epithelial TGF-β signaling via TGF-β receptor II (TβRII) and its contribution to fibrosis by generating mice in which TβRII was specifically inactivated in mouse lung epithelium. These mice, which are referred to herein as TβRIINkx2.1-cre mice, were used to determine the impact of TβRII inactivation on (a) embryonic lung morphogenesis in vivo; and (b) the epithelial cell response to TGF-β signaling in vitro and in a bleomycin-induced, TGF-β-mediated mouse model of pulmonary fibrosis. Although postnatally viable with no discernible abnormalities in lung morphogenesis and epithelial cell differentiation, TβRIINkx2.1-cre mice developed emphysema, suggesting a requirement for epithelial TβRII in alveolar homeostasis. Absence of TβRII increased phosphorylation of Smad2 and decreased, but did not entirely block, phosphorylation of Smad3 in response to endogenous/physiologic TGF-β. However, TβRIINkx2.1-cre mice exhibited increased survival and resistance to bleomycin-induced pulmonary fibrosis. To our knowledge, these findings are the first to demonstrate a specific role for TGF-β signaling in the lung epithelium in the pathogenesis of pulmonary fibrosis.
American Journal of Respiratory Cell and Molecular Biology | 2011
Qian Zhong; Beiyun Zhou; David K. Ann; Parviz Minoo; Yixin Liu; Agnes Banfalvi; Manda S. Krishnaveni; Mickael Dubourd; Lucas DeMaio; Brigham C. Willis; Kwang-Jin Kim; Roland M. duBois; Edward D. Crandall; Michael F. Beers; Zea Borok
Endoplasmic reticulum (ER) stress has been implicated in alveolar epithelial type II (AT2) cell apoptosis in idiopathic pulmonary fibrosis. We hypothesized that ER stress (either chemically induced or due to accumulation of misfolded proteins) is also associated with epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs). ER stress inducers, thapsigargin (TG) or tunicamycin (TN), increased expression of ER chaperone, Grp78, and spliced X-box binding protein 1, decreased epithelial markers, E-cadherin and zonula occludens-1 (ZO-1), increased the myofibroblast marker, α-smooth muscle actin (α-SMA), and induced fibroblast-like morphology in both primary AECs and the AT2 cell line, RLE-6TN, consistent with EMT. Overexpression of the surfactant protein (SP)-C BRICHOS mutant SP-C(ΔExon4) in A549 cells increased Grp78 and α-SMA and disrupted ZO-1 distribution, and, in primary AECs, SP-C(ΔExon4) induced fibroblastic-like morphology, decreased ZO-1 and E-cadherin and increased α-SMA, mechanistically linking ER stress associated with mutant SP to fibrosis through EMT. Whereas EMT was evident at lower concentrations of TG or TN, higher concentrations caused apoptosis. The Src inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4]pyramidine) (PP2), abrogated EMT associated with TN or TG in primary AECs, whereas overexpression of SP-C(ΔExon4) increased Src phosphorylation, suggesting a common mechanism. Furthermore, increased Grp78 immunoreactivity was observed in AT2 cells of mice after bleomycin injury, supporting a role for ER stress in epithelial abnormalities in fibrosis in vivo. These results demonstrate that ER stress induces EMT in AECs, at least in part through Src-dependent pathways, suggesting a novel role for ER stress in fibroblast accumulation in pulmonary fibrosis.
American Journal of Physiology-lung Cellular and Molecular Physiology | 2008
Janice M. Liebler; Carolyn Lutzko; Agnes Banfalvi; Dinithi Senadheera; Neema Aghamohammadi; Edward D. Crandall; Zea Borok
We studied the capacity of adult human bone marrow-derived cells (BMDC) to incorporate into distal lung of immunodeficient mice following lung injury. Immunodeficient NOD/SCID and NOD/SCID/beta(2) microglobulin (beta(2)M)(null) mice were administered bleomycin (bleo) or saline intranasally. One, 2, 3 and 4 days after bleo or saline, human BMDC labeled with CellTracker Green CMFDA (5-chloromethylfluorescein diacetate) were infused intravenously. Retention of CMFDA(+) cells was maximal when delivered 4 days after bleo treatment. Seven days after bleo, <0.005% of enzymatically dispersed lung cells from NOD/SCID mice were CMFDA(+), which increased 10- to 100-fold in NOD/SCID/beta(2)M(null) mice. Preincubation of BMDC with Diprotin A, a reversible inhibitor of CD26 peptidase activity that enhances the stromal-derived factor-1 (SDF-1/CXCL12)/CXCR4 axis, resulted in a 30% increase in the percentage of CMFDA(+) cells retained in the lung. These data indicate that human BMDC can be identified in lungs of mice following injury, albeit at low levels, and this may be modestly enhanced by manipulation of the SDF-1/CXCR4 axis. Given the overall low number of human cells detected, methods to increase homing and retention of adult BMDC, and consideration of other stem cell populations, will likely be required to facilitate engraftment in the treatment of lung injury.
American Journal of Respiratory Cell and Molecular Biology | 2010
Per Flodby; Zea Borok; Agnes Banfalvi; Beiyun Zhou; Danping Gao; Parviz Minoo; David K. Ann; Edward E. Morrisey; Edward D. Crandall
Pulmonary alveolar epithelium is comprised of two morphologically and functionally distinct cell types, alveolar epithelial type (AT) I and AT2 cells. Genetically modified mice with cell-specific Cre/loxP-mediated knockouts of relevant genes in each respective cell type would be useful to help elucidate the relative contributions of AT1 versus AT2 cells to alveolar homeostasis. Cre has previously been efficiently expressed in AT2 cells in mouse lung with the surfactant protein (SP)-C promoter; however, no transgenic mouse expressing Cre in AT1 cells has so far been available. To develop an AT1 cell-specific transgenic Cre mouse, we generated a knockin of a Cre-IRES-DsRed cassette into exon 1 of the endogenous aquaporin 5 (Aqp5) gene, a gene expressed specifically in AT1 cells in the distal lung epithelium, resulting in the mouse line, Aqp5-Cre-IRES-DsRed (ACID). Endogenous Aqp5 and transgenic Cre in ACID mice showed a very similar pattern of tissue distribution by RT-PCR. To analyze Cre activity, ACID was crossed to two Cre reporter strains, R26LacZ and mT/mG. Double-transgenic offspring demonstrated reporter gene expression in a very high fraction of AT1 cells in the distal lung, whereas AT2 cells were negative. As expected, variable reporter expression was detected in several other tissues where endogenous Aqp5 is expressed (e.g., submandibular salivary gland and stomach). ACID mice should be of major utility in analyzing the functional contribution of AT1 cells to alveolar epithelial properties in vivo with Cre/loxP-mediated gene deletion technology.
The Journal of Pathology | 2012
Lucas DeMaio; Stephen T. Buckley; Manda S. Krishnaveni; Per Flodby; Mickael Dubourd; Agnes Banfalvi; Yiming Xing; Carsten Ehrhardt; Parviz Minoo; Beiyun Zhou; Edward D. Crandall; Zea Borok
Evidence suggests epithelial–mesenchymal transition (EMT) as one potential source of fibroblasts in idiopathic pulmonary fibrosis. To assess the contribution of alveolar epithelial cell (AEC) EMT to fibroblast accumulation in vivo following lung injury and the influence of extracellular matrix on AEC phenotype in vitro, Nkx2.1‐Cre;mT/mG mice were generated in which AECs permanently express green fluorescent protein (GFP). On days 17–21 following intratracheal bleomycin administration, ∼4% of GFP‐positive epithelial‐derived cells expressed vimentin or α‐smooth muscle actin (α‐SMA). Primary AECs from Nkx2.1‐Cre;mT/mG mice cultured on laminin‐5 or fibronectin maintained an epithelial phenotype. In contrast, on type I collagen, cells of epithelial origin displayed nuclear localization of Smad3, acquired spindle‐shaped morphology, expressed α‐SMA and phospho‐Smad3, consistent with activation of the transforming growth factor‐β (TGFβ) signalling pathway and EMT. α‐SMA induction and Smad3 nuclear localization were blocked by the TGFβ type I receptor (TβRI, otherwise known as Alk5) inhibitor SB431542, while AEC derived from Nkx2.1‐Cre;Alk5
American Journal of Physiology-lung Cellular and Molecular Physiology | 2017
Per Flodby; Janice M. Liebler; Mitsuhiro Sunohara; Dan R. Castillo; Alicia M. McConnell; Manda S. Krishnaveni; Agnes Banfalvi; Min Li; Barry R. Stripp; Beiyun Zhou; Edward D. Crandall; Parviz Minoo; Zea Borok
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Clinical Immunology | 2016
William Stohl; Agnes Banfalvi
mice did not undergo EMT on collagen, consistent with a requirement for signalling via Alk5 in collagen‐induced EMT. Inability of a pan‐specific TGFβ neutralizing antibody to inhibit effects of collagen together with absence of active TGFβ in culture supernatants is consistent with TGFβ ligand‐independent activation of Smad signalling. These results support the notion that AECs can acquire a mesenchymal phenotype following injury in vivo and implicate type I collagen as a key regulator of EMT in AECs through signalling via Alk5, likely in a TGFβ ligand‐independent manner. Copyright
american thoracic society international conference | 2011
Lucas DeMaio; Stephen T. Buckley; Per Flodby; Agnes Banfalvi; Manda S. Krishnaveni; Yiming Xing; Carsten Ehrhardt; Parviz Minoo; Edward D. Crandall; Zea Borok
Previous studies have demonstrated resistance to naphthalene-induced injury in proximal airways of mice with lung epithelial-specific deletion of the tumor-suppressor gene Pten, attributed to increased proliferation of airway progenitors. We tested effects of Pten loss following bleomycin injury, a model typically used to study distal lung epithelial injury, in conditional PtenSFTPC-cre knockout mice. Pten-deficient airway epithelium exhibited marked hyperplasia, particularly in small bronchioles and at bronchoalveolar duct junctions, with reduced E-cadherin and β-catenin expression between cells toward the luminal aspect of the hyperplastic epithelium. Bronchiolar epithelial and alveolar epithelial type II (AT2) cells in PtenSFTPC-cre mice showed decreased expression of epithelial markers and increased expression of mesenchymal markers, suggesting at least partial epithelial-mesenchymal transition at baseline. Surprisingly, and in contrast to previous studies, mutant mice were exquisitely sensitive to bleomycin, manifesting rapid weight loss, respiratory distress, increased early mortality (by day 5), and reduced dynamic lung compliance. This was accompanied by sloughing of the hyperplastic airway epithelium with occlusion of small bronchioles by cellular debris, without evidence of increased parenchymal lung injury. Increased airway epithelial cell apoptosis due to loss of antioxidant defenses, reflected by decreased expression of superoxide dismutase 3, in combination with deficient intercellular adhesion, likely predisposed to airway sloughing in knockout mice. These findings demonstrate an important role for Pten in maintenance of airway epithelial phenotype integrity and indicate that responses to Pten deletion in respiratory epithelium following acute lung injury are highly context-dependent and region-specific.
american thoracic society international conference | 2011
Per Flodby; Zea Borok; Danping Gao; Yong-Ho Kim; Agnes Banfalvi; Kwang-Jin Kim; Edward D. Crandall
BAFF blockade is efficacious in murine and human SLE. Whereas the attendant reduction in B cells contributes to the efficacy, it remains unresolved whether a B cell-independent component also contributes. Since accurate assessment of a B cell-independent component can only be made in a B cell-independent autoimmune disease, we investigated MOG35-55-induced EAE in C57BL/6 mice. Neither pharmacologic neutralization nor genetic elimination of BAFF affected disease, nor did elimination of APRIL (with or without elimination of BAFF) or constitutive over-expression of BAFF. Eliminating BAFF had no effect on disease even in mice that were genetically manipulated to maintain greater-than-normal numbers of B cells. However, elimination of BAFF in B cell-deficient mice dramatically reduced disease, thereby unmasking a B cell-independent contribution of BAFF to an autoimmune disease. Our findings raise the plausibility that BAFF contributes to SLE not only through effects on B cells but through B cell-independent pathways as well.
american thoracic society international conference | 2010
Janice M. Liebler; Lucas DeMaio; Qian Zhong; Per Flodby; Agnes Banfalvi; Kwang-Jin Kim; Edward D. Crandall; Zea Borok