Person:
Mammoto, Akiko

Profile Picture

Email Address

AA Acceptance Date

Birth Date

Research Projects

Organizational Units

Job Title

Last Name

Mammoto

First Name

Akiko

Name

Mammoto, Akiko
Author's Publications: search.filters.isAuthorOfPublication.011d41f1-0fcf-475e-88df-660bfc31497f

Search Results

Now showing 1 - 9 of 9
  • Thumbnail Image
    Publication
    Twist1 Controls Lung Vascular Permeability and Endotoxin-Induced Pulmonary Edema by Altering Tie2 Expression
    (Public Library of Science, 2013) Mammoto, Tadanori; Jiang, Elisabeth; Jiang, Amanda; Lu, Yongbo; Juan, Aimee M.; Chen, Jing; Mammoto, Akiko
    Tight regulation of vascular permeability is necessary for normal development and deregulated vascular barrier function contributes to the pathogenesis of various diseases, including acute respiratory distress syndrome, cancer and inflammation. The angiopoietin (Ang)-Tie2 pathway is known to control vascular permeability. However, the mechanism by which the expression of Tie2 is regulated to control vascular permeability has not been fully elucidated. Here we show that transcription factor Twist1 modulates pulmonary vascular leakage by altering the expression of Tie2 in a context-dependent way. Twist1 knockdown in cultured human lung microvascular endothelial cells decreases Tie2 expression and phosphorylation and increases RhoA activity, which disrupts cell-cell junctional integrity and increases vascular permeability in vitro. In physiological conditions, where Ang1 is dominant, pulmonary vascular permeability is elevated in the Tie2-specific Twist1 knockout mice. However, depletion of Twist1 and resultant suppression of Tie2 expression prevent increase in vascular permeability in an endotoxin-induced lung injury model, where the balance of Angs shifts toward Ang2. These results suggest that Twist1-Tie2-Angs signaling is important for controlling vascular permeability and modulation of this mechanism may lead to the development of new therapeutic approaches for pulmonary edema and other diseases caused by abnormal vascular permeability.
  • Thumbnail Image
    Publication
    Bone Marrow–on–a–Chip Replicates Hematopoietic Niche Physiology in Vitro
    (Nature Publishing Group, 2014) Torisawa, Yu-suke; Spina, Catherine S; Mammoto, Tadanori; Mammoto, Akiko; Weaver, James; Tat, Tracy; Collins, James; Ingber, Donald
    Current in vitro hematopoiesis models fail to demonstrate the cellular diversity and complex functions of living bone marrow; hence, most translational studies relevant to the hematologic system are conducted in live animals. Here we describe a method for fabricating 'bone marrow–on–a–chip' that permits culture of living marrow with a functional hematopoietic niche in vitro by first engineering new bone in vivo, removing it whole and perfusing it with culture medium in a microfluidic device. The engineered bone marrow (eBM) retains hematopoietic stem and progenitor cells in normal in vivo–like proportions for at least 1 week in culture. eBM models organ-level marrow toxicity responses and protective effects of radiation countermeasure drugs, whereas conventional bone marrow culture methods do not. This biomimetic microdevice offers a new approach for analysis of drug responses and toxicities in bone marrow as well as for study of hematopoiesis and hematologic diseases in vitro.
  • Thumbnail Image
    Publication
    Wnt Signaling Mediates Pathological Vascular Growth in Proliferative Retinopathy Clinical Perspective
    (Ovid Technologies (Wolters Kluwer Health), 2011) Chen, Jing; Stahl, Andreas; Krah, Nathan M.; Seaward, Molly R.; Dennison, Roberta; Sapieha, Przemyslaw; Hua, Jing; Hatton, Colman J.; Juan, Aimee M.; Aderman, Christopher; Willett, Keirnan L.; Guerin, Karen I.; Mammoto, Akiko; Campbell, Matthew; Smith, Lois
    BACKGROUND: Ischemic proliferative retinopathy, characterized by pathological retinal neovascularization, is a major cause of blindness in working-age adults and children. Defining the molecular pathways distinguishing pathological neovascularization from normal vessels is critical to controlling these blinding diseases with targeted therapy. Because mutations in Wnt signaling cause defective retinal vasculature in humans with some characteristics of the pathological vessels in retinopathy, we investigated the potential role of Wnt signaling in pathological retinal vascular growth in proliferative retinopathy. METHODS AND RESULTS: In this study, we show that Wnt receptors (Frizzled4 and low-density lipoprotein receptor-related protein5 [Lrp5]) and activity are significantly increased in pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Loss of Wnt coreceptor Lrp5 and downstream signaling molecule dishevelled2 significantly decreases the formation of pathological retinal neovascularization in retinopathy. Loss of Lrp5 also affects retinal angiogenesis during development and formation of the blood-retinal barrier, which is linked to significant downregulation of tight junction protein claudin5 in Lrp5(-/-) vessels. Blocking claudin5 significantly suppresses Wnt pathway-driven endothelial cell sprouting in vitro and developmental and pathological vascular growth in retinopathy in vivo. CONCLUSIONS: These results demonstrate an important role of Wnt signaling in pathological vascular development in retinopathy and show a novel function of Cln5 in promoting angiogenesis.
  • Thumbnail Image
    Publication
    Multizone Paper Platform for 3D Cell Cultures
    (Public Library of Science (PLoS), 2011) Derda, Ratmir; Tang, Sindy K. Y.; Laromaine, Anna; Mosadegh, Bobak; Hong, Estrella; Mwangi, Martin; Mammoto, Akiko; Ingber, Donald; Whitesides, George
    In vitro 3D culture is an important model for tissues in vivo. Cells in different locations of 3D tissues are physiologically different, because they are exposed to different concentrations of oxygen, nutrients, and signaling molecules, and to other environmental factors (temperature, mechanical stress, etc). The majority of high-throughput assays based on 3D cultures, however, can only detect the average behavior of cells in the whole 3D construct. Isolation of cells from specific regions of 3D cultures is possible, but relies on low-throughput techniques such as tissue sectioning and micromanipulation. Based on a procedure reported previously (“cells-in-gels-in-paper” or CiGiP), this paper describes a simple method for culture of arrays of thin planar sections of tissues, either alone or stacked to create more complex 3D tissue structures. This procedure starts with sheets of paper patterned with hydrophobic regions that form 96 hydrophilic zones. Serial spotting of cells suspended in extracellular matrix (ECM) gel onto the patterned paper creates an array of 200 micron-thick slabs of ECM gel (supported mechanically by cellulose fibers) containing cells. Stacking the sheets with zones aligned on top of one another assembles 96 3D multilayer constructs. De-stacking the layers of the 3D culture, by peeling apart the sheets of paper, “sections” all 96 cultures at once. It is, thus, simple to isolate 200-micron-thick cell-containing slabs from each 3D culture in the 96-zone array. Because the 3D cultures are assembled from multiple layers, the number of cells plated initially in each layer determines the spatial distribution of cells in the stacked 3D cultures. This capability made it possible to compare the growth of 3D tumor models of different spatial composition, and to examine the migration of cells in these structures.
  • Thumbnail Image
    Publication
    TWIST1 Integrates Endothelial Responses to Flow in Vascular Dysfunction and Atherosclerosis
    (Lippincott Williams & Wilkins, 2016) Mahmoud, Marwa M.; Kim, Hyejeong Rosemary; Xing, Rouyu; Hsiao, Sarah; Mammoto, Akiko; Chen, Jing; Serbanovic-Canic, Jovana; Feng, Shuang; Bowden, Neil P.; Maguire, Richard; Ariaans, Markus; Francis, Sheila E.; Weinberg, Peter D.; van der Heiden, Kim; Jones, Elizabeth A.; Chico, Timothy J.A.; Ridger, Victoria; Evans, Paul C.
    Rationale: Blood flow–induced shear stress controls endothelial cell (EC) physiology during atherosclerosis via transcriptional mechanisms that are incompletely understood. The mechanosensitive transcription factor TWIST is expressed during embryogenesis, but its role in EC responses to shear stress and focal atherosclerosis is unknown. Objective: To investigate whether TWIST regulates endothelial responses to shear stress during vascular dysfunction and atherosclerosis and compare TWIST function in vascular development and disease. Methods and Results: The expression and function of TWIST1 was studied in EC in both developing vasculature and during the initiation of atherosclerosis. In zebrafish, twist was expressed in early embryonic vasculature where it promoted angiogenesis by inducing EC proliferation and migration. In adult porcine and murine arteries, TWIST1 was expressed preferentially at low shear stress regions as evidenced by quantitative polymerase chain reaction and en face staining. Moreover, studies of experimental murine carotid arteries and cultured EC revealed that TWIST1 was induced by low shear stress via a GATA4-dependent transcriptional mechanism. Gene silencing in cultured EC and EC-specific genetic deletion in mice demonstrated that TWIST1 promoted atherosclerosis by inducing inflammation and enhancing EC proliferation associated with vascular leakiness. Conclusions: TWIST expression promotes developmental angiogenesis by inducing EC proliferation and migration. In addition to its role in development, TWIST is expressed preferentially at low shear stress regions of adult arteries where it promotes atherosclerosis by inducing EC proliferation and inflammation. Thus, pleiotropic functions of TWIST control vascular disease and development.
  • Thumbnail Image
    Publication
    VEGF-A/NRP1 stimulates GIPC1 and Syx complex formation to promote RhoA activation and proliferation in skin cancer cells
    (The Company of Biologists, 2015) Yoshida, Ayumi; Shimizu, Akio; Asano, Hirotsugu; Kadonosono, Tetsuya; Kondoh, Shinae Kizaka; Geretti, Elena; Mammoto, Akiko; Klagsbrun, Michael; Seo, Misuzu Kurokawa
    ABSTRACT Neuropilin-1 (NRP1) has been identified as a VEGF-A receptor. DJM-1, a human skin cancer cell line, expresses endogenous VEGF-A and NRP1. In the present study, the RNA interference of VEGF-A or NRP1 suppressed DJM-1 cell proliferation. Furthermore, the overexpression of the NRP1 wild type restored shNRP1-treated DJM-1 cell proliferation, whereas NRP1 cytoplasmic deletion mutants did not. A co-immunoprecipitation analysis revealed that VEGF-A induced interactions between NRP1 and GIPC1, a scaffold protein, and complex formation between GIPC1 and Syx, a RhoGEF. The knockdown of GIPC1 or Syx reduced active RhoA and DJM-1 cell proliferation without affecting the MAPK or Akt pathway. C3 exoenzyme or Y27632 inhibited the VEGF-A-induced proliferation of DJM-1 cells. Conversely, the overexpression of the constitutively active form of RhoA restored the proliferation of siVEGF-A-treated DJM-1 cells. Furthermore, the inhibition of VEGF-A/NRP1 signaling upregulated p27, a CDK inhibitor. A cell-penetrating oligopeptide that targeted GIPC1/Syx complex formation inhibited the VEGF-A-induced activation of RhoA and suppressed DJM-1 cell proliferation. In conclusion, this new signaling pathway of VEGF-A/NRP1 induced cancer cell proliferation by forming a GIPC1/Syx complex that activated RhoA to degrade the p27 protein.
  • Thumbnail Image
    Publication
    Matrix Elasticity of Void-Forming Hydrogels Controls Transplanted Stem Cell-Mediated Bone Formation
    (2015) Huebsch, Nathaniel; Lippens, Evi; Lee, Kangwon; Mehta, Manav; Koshy, Sandeep; Darnell, Max; Desai, Rajiv; Madl, Christopher M.; Xu, Maria; Zhao, Xuanhe; Chaudhuri, Ovijit; Verbeke, Catia; Kim, Woo Seob; Alim, Karen; Mammoto, Akiko; Ingber, Donald; Duda, Georg N; Mooney, David
    The effectiveness of stem-cell therapies has been hampered by cell death and limited control over fate1. These problems can be partially circumvented by using macroporous biomaterials that improve the survival of transplanted stem cells and provide molecular cues to direct cell phenotype2–4. Stem cell behavior can also be controlled in vitro by manipulating the elasticity of both porous and non-porous materials5–7, yet translation to therapeutic processes in vivo remains elusive. Here, by developing injectable, void-forming hydrogels that decouple pore formation from elasticity, we show that mesenchymal stem cell (MSC) osteogenesis in vitro, and cell deployment in vitro and in vivo, can be controlled by modifying, respectively, the hydrogel's elastic modulus or its chemistry. When the hydrogels were used to transplant MSCs, the hydrogel's elasticity regulated bone regeneration, with optimal bone formation at 60 kPa. Our findings show that biophysical cues can be harnessed to direct therapeutic stem-cell behaviors in situ.
  • Thumbnail Image
    Publication
    LRP5 Regulates Development of Lung Microvessels and Alveoli through the Angiopoietin-Tie2 Pathway
    (Public Library of Science, 2012) Mammoto, Tadanori; Jiang, Amanda; Jiang, Elizabeth; Mammoto, Akiko; Chen, Jing; Smith, Lois; Ingber, Donald
    Angiogenesis is crucial for lung development. Although there has been considerable exploration, the mechanism by which lung vascular and alveolar formation is controlled is still not completely understood. Here we show that low-density lipoprotein receptor-related protein 5 (LRP5), a component of the Wnt ligand-receptor complex, regulates angiogenesis and alveolar formation in the lung by modulating expression of the angiopoietin (Ang) receptor, Tie2, in vascular endothelial cells (ECs). Vascular development in whole mouse lungs and in cultured ECs is controlled by LRP5 signaling, which is, in turn, governed by a balance between the activities of the antagonistic Tie2 ligands, Ang1 and Ang2. Under physiological conditions when Ang1 is dominant, LRP5 knockdown decreases Tie2 expression and thereby, inhibits vascular and alveolar development in the lung. Conversely, when Ang2 dominates under hyperoxia treatment in neonatal mice, high LRP5 and Tie2 expression suppress angiogenesis and lung development. These findings suggest that the LRP5-Tie2-Ang signaling axis plays a central role in control of both angiogenesis and alveolarization during postnatal lung development, and that deregulation of this signaling mechanism might lead to developmental abnormalities of the lung, such as are observed in bronchopulmonary dysplasia (BPD).
  • Thumbnail Image
    Publication
    A Mechanosensitive Transcriptional Mechanism That Controls Angiogenesis
    (Nature Publishing Group, 2009) Mammoto, Akiko; Connor, Kip; Mammoto, Tadanori; Yung, Chong W.; Huh, Dongeun; Aderman, Christopher; Mostoslavsky, Gustavo; Smith, Lois; Ingber, Donald
    Angiogenesis is controlled by physical interactions between cells and extracellular matrix as well as soluble angiogenic factors, such as VEGF. However, the mechanism by which mechanical signals integrate with other microenvironmental cues to regulate neovascularization remains unknown. Here we show that the Rho inhibitor, p190RhoGAP (also known as GRLF1), controls capillary network formation in vitro in human microvascular endothelial cells and retinal angiogenesis in vivo by modulating the balance of activities between two antagonistic transcription factors, TFII-I (also known as GTF2I) and GATA2, that govern gene expression of the VEGF receptor VEGFR2 (also known as KDR). Moreover, this new angiogenesis signalling pathway is sensitive to extracellular matrix elasticity as well as soluble VEGF. This is, to our knowledge, the first known functional cross-antagonism between transcription factors that controls tissue morphogenesis, and that responds to both mechanical and chemical cues.