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Hurwitz B, Guzzi N, Gola A, Fiore VF, Sendoel A, Nikolova M, Barrows D, Carroll TS, Pasolli HA, Fuchs E. The integrated stress response remodels the microtubule-organizing center to clear unfolded proteins following proteotoxic stress. eLife 2022; 11:e77780. [PMID: 35758650 PMCID: PMC9299849 DOI: 10.7554/elife.77780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Cells encountering stressful situations activate the integrated stress response (ISR) pathway to limit protein synthesis and redirect translation to better cope. The ISR has also been implicated in cancers, but redundancies in the stress-sensing kinases that trigger the ISR have posed hurdles to dissecting physiological relevance. To overcome this challenge, we targeted the regulatory node of these kinases, namely, the S51 phosphorylation site of eukaryotic translation initiation factor eIF2α and genetically replaced eIF2α with eIF2α-S51A in mouse squamous cell carcinoma (SCC) stem cells of skin. While inconsequential under normal growth conditions, the vulnerability of this ISR-null state was unveiled when SCC stem cells experienced proteotoxic stress. Seeking mechanistic insights into the protective roles of the ISR, we combined ribosome profiling and functional approaches to identify and probe the functional importance of translational differences between ISR-competent and ISR-null SCC stem cells when exposed to proteotoxic stress. In doing so, we learned that the ISR redirects translation to centrosomal proteins that orchestrate the microtubule dynamics needed to efficiently concentrate unfolded proteins at the microtubule-organizing center so that they can be cleared by the perinuclear degradation machinery. Thus, rather than merely maintaining survival during proteotoxic stress, the ISR also functions in promoting cellular recovery once the stress has subsided. Remarkably, this molecular program is unique to transformed skin stem cells, hence exposing a vulnerability in cancer that could be exploited therapeutically.
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Affiliation(s)
- Brian Hurwitz
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller UniversityNew YorkUnited States
| | - Nicola Guzzi
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller UniversityNew YorkUnited States
| | - Anita Gola
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller UniversityNew YorkUnited States
| | - Vincent F Fiore
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller UniversityNew YorkUnited States
| | - Ataman Sendoel
- Institute for Regenerative Medicine, University of ZurichZurichSwitzerland
| | - Maria Nikolova
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller UniversityNew YorkUnited States
| | - Douglas Barrows
- Bioinformatics Resource Center, The Rockefeller UniversityNew YorkUnited States
| | - Thomas S Carroll
- Bioinformatics Resource Center, The Rockefeller UniversityNew YorkUnited States
| | - H Amalia Pasolli
- Electron Microscopy Resource Center, The Rockefeller UniversityNew YorkUnited States
| | - Elaine Fuchs
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller UniversityNew YorkUnited States
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2
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Fiore VF, Krajnc M, Quiroz FG, Levorse J, Pasolli HA, Shvartsman SY, Fuchs E. Mechanics of a multilayer epithelium instruct tumour architecture and function. Nature 2020; 585:433-439. [PMID: 32879493 DOI: 10.1038/s41586-020-2695-9] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 07/22/2020] [Indexed: 01/24/2023]
Abstract
Loss of normal tissue architecture is a hallmark of oncogenic transformation1. In developing organisms, tissues architectures are sculpted by mechanical forces during morphogenesis2. However, the origins and consequences of tissue architecture during tumorigenesis remain elusive. In skin, premalignant basal cell carcinomas form 'buds', while invasive squamous cell carcinomas initiate as 'folds'. Here, using computational modelling, genetic manipulations and biophysical measurements, we identify the biophysical underpinnings and biological consequences of these tumour architectures. Cell proliferation and actomyosin contractility dominate tissue architectures in monolayer, but not multilayer, epithelia. In stratified epidermis, meanwhile, softening and enhanced remodelling of the basement membrane promote tumour budding, while stiffening of the basement membrane promotes folding. Additional key forces stem from the stratification and differentiation of progenitor cells. Tumour-specific suprabasal stiffness gradients are generated as oncogenic lesions progress towards malignancy, which we computationally predict will alter extensile tensions on the tumour basement membrane. The pathophysiologic ramifications of this prediction are profound. Genetically decreasing the stiffness of basement membranes increases membrane tensions in silico and potentiates the progression of invasive squamous cell carcinomas in vivo. Our findings suggest that mechanical forces-exerted from above and below progenitors of multilayered epithelia-function to shape premalignant tumour architectures and influence tumour progression.
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Affiliation(s)
- Vincent F Fiore
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY, USA
| | - Matej Krajnc
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.,Jozef Stefan Institute, Ljubljana, Slovenia
| | - Felipe Garcia Quiroz
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY, USA.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - John Levorse
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY, USA
| | - H Amalia Pasolli
- Electron Microscopy Resource Center, The Rockefeller University, New York, NY, USA
| | - Stanislav Y Shvartsman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Elaine Fuchs
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY, USA.
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3
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Quiroz FG, Fiore VF, Levorse J, Polak L, Wong E, Pasolli HA, Fuchs E. Liquid-liquid phase separation drives skin barrier formation. Science 2020; 367:367/6483/eaax9554. [PMID: 32165560 DOI: 10.1126/science.aax9554] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 11/20/2019] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
At the body surface, skin's stratified squamous epithelium is challenged by environmental extremes. The surface of the skin is composed of enucleated, flattened surface squames. They derive from underlying, transcriptionally active keratinocytes that display filaggrin-containing keratohyalin granules (KGs) whose function is unclear. Here, we found that filaggrin assembles KGs through liquid-liquid phase separation. The dynamics of phase separation governed terminal differentiation and were disrupted by human skin barrier disease-associated mutations. We used fluorescent sensors to investigate endogenous phase behavior in mice. Phase transitions during epidermal stratification crowded cellular spaces with liquid-like KGs whose coalescence was restricted by keratin filament bundles. We imaged cells as they neared the skin surface and found that environmentally regulated KG phase dynamics drive squame formation. Thus, epidermal structure and function are driven by phase-separation dynamics.
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Affiliation(s)
- Felipe Garcia Quiroz
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA
| | - Vincent F Fiore
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA
| | - John Levorse
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA
| | - Lisa Polak
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA
| | - Ellen Wong
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA
| | - H Amalia Pasolli
- Electron Microscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Elaine Fuchs
- Howard Hughes Medical Institute, Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA.
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Fiore VF, Wong SS, Tran C, Tan C, Xu W, Sulchek T, White ES, Hagood JS, Barker TH. αvβ3 Integrin drives fibroblast contraction and strain stiffening of soft provisional matrix during progressive fibrosis. JCI Insight 2018; 3:97597. [PMID: 30333317 DOI: 10.1172/jci.insight.97597] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 08/30/2018] [Indexed: 12/11/2022] Open
Abstract
Fibrosis is characterized by persistent deposition of extracellular matrix (ECM) by fibroblasts. Fibroblast mechanosensing of a stiffened ECM is hypothesized to drive the fibrotic program; however, the spatial distribution of ECM mechanics and their derangements in progressive fibrosis are poorly characterized. Importantly, fibrosis presents with significant histopathological heterogeneity at the microscale. Here, we report that fibroblastic foci (FF), the regions of active fibrogenesis in idiopathic pulmonary fibrosis (IPF), are surprisingly of similar modulus as normal lung parenchyma and are nonlinearly elastic. In vitro, provisional ECMs with mechanical properties similar to those of FF activate both normal and IPF patient-derived fibroblasts, whereas type I collagen ECMs with similar mechanical properties do not. This is mediated, in part, by αvβ3 integrin engagement and is augmented by loss of expression of Thy-1, which regulates αvβ3 integrin avidity for ECM. Thy-1 loss potentiates cell contractility-driven strain stiffening of provisional ECM in vitro and causes elevated αvβ3 integrin activation, increased fibrosis, and greater mortality following fibrotic lung injury in vivo. These data suggest a central role for αvβ3 integrin and provisional ECM in overriding mechanical cues that normally impose quiescent phenotypes, driving progressive fibrosis through physical stiffening of the fibrotic niche.
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Affiliation(s)
- Vincent F Fiore
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Simon S Wong
- Department of Pediatrics, Division of Pediatric Respiratory Medicine, University of California, San Diego, La Jolla, California, USA
| | - Coleen Tran
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Chunting Tan
- Department of Pediatrics, Division of Pediatric Respiratory Medicine, University of California, San Diego, La Jolla, California, USA
| | - Wenwei Xu
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Todd Sulchek
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Eric S White
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - James S Hagood
- Department of Pediatrics, Division of Pediatric Respiratory Medicine, University of California, San Diego, La Jolla, California, USA.,Rady Children's Hospital of San Diego, San Diego, California, USA
| | - Thomas H Barker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
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Ouspenskaia T, Matos I, Mertz AF, Fiore VF, Fuchs E. WNT-SHH Antagonism Specifies and Expands Stem Cells prior to Niche Formation. Cell 2016; 164:156-169. [PMID: 26771489 DOI: 10.1016/j.cell.2015.11.058] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/15/2015] [Accepted: 11/18/2015] [Indexed: 12/15/2022]
Abstract
Adult stem cell (SC) maintenance and differentiation are known to depend on signals received from the niche. Here, however, we demonstrate a mechanism for SC specification and regulation that is niche independent. Using immunofluorescence, live imaging, genetics, cell-cycle analyses, in utero lentiviral transduction, and lineage-tracing, we show that in developing hair buds, SCs are born from asymmetric divisions that differentially display WNT and SHH signaling. Displaced WNT(lo) suprabasal daughters become SCs that respond to paracrine SHH and symmetrically expand. By contrast, basal daughters remain WNT(hi). They express but do not respond to SHH and hence maintain slow-cycling, asymmetric divisions. Over time, they become short-lived progenitors, generating differentiating daughters rather than SCs. Thus, in contrast to an established niche that harbors a fixed SC pool whose expelled progeny differentiate, asymmetric divisions first specify and displace early SCs into an environment conducive to expansion and later restrict their numbers by switching asymmetric fates.
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Affiliation(s)
- Tamara Ouspenskaia
- Robin Neustein Laboratory of Mammalian Development and Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Irina Matos
- Robin Neustein Laboratory of Mammalian Development and Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Aaron F Mertz
- Robin Neustein Laboratory of Mammalian Development and Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Vincent F Fiore
- Robin Neustein Laboratory of Mammalian Development and Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Elaine Fuchs
- Robin Neustein Laboratory of Mammalian Development and Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA.
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Fiore VF, Strane PW, Bryksin AV, White ES, Hagood JS, Barker TH. Conformational coupling of integrin and Thy-1 regulates Fyn priming and fibroblast mechanotransduction. J Cell Biol 2016; 211:173-90. [PMID: 26459603 PMCID: PMC4602038 DOI: 10.1083/jcb.201505007] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Lateral associations between inactive αv integrin and Thy-1 glycoprotein control integrin avidity to extracellular matrix ligand, the localization and kinetics of downstream signal activity, and mechanosensitive remodeling of the cytoskeleton. Progressive fibrosis is characterized by excessive deposition of extracellular matrix (ECM), resulting in gross alterations in tissue mechanics. Changes in tissue mechanics can further augment scar deposition through fibroblast mechanotransduction. In idiopathic pulmonary fibrosis, a fatal form of progressive lung fibrosis, previous work has shown that loss of Thy-1 (CD90) expression in fibroblasts correlates with regions of active fibrogenesis, thus representing a pathologically relevant fibroblast subpopulation. We now show that Thy-1 is a regulator of fibroblast rigidity sensing. Thy-1 physically couples to inactive αvβ3 integrins via its RGD-like motif, altering baseline integrin avidity to ECM ligands and also facilitating preadhesion clustering of integrin and membrane rafts via Thy-1’s glycophosphatidylinositol tether. Disruption of Thy-1–αvβ3 coupling altered recruitment of Src family kinases to adhesion complexes and impaired mechanosensitive, force-induced Rho signaling, and rigidity sensing. Loss of Thy-1 was sufficient to induce myofibroblast differentiation in soft ECMs and may represent a physiological mechanism important in wound healing and fibrosis.
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Affiliation(s)
- Vincent F Fiore
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
| | - Patrick W Strane
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
| | - Anton V Bryksin
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
| | - Eric S White
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - James S Hagood
- Division of Respiratory Medicine, Department of Pediatrics, University of California, Rady Children's Hospital, San Diego, CA 92105
| | - Thomas H Barker
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332
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7
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Fiore VF, Strane PW, Bryksin AV, White ES, Hagood JS, Barker TH. Conformational coupling of integrin and Thy-1 regulates Fyn priming and fibroblast mechanotransduction. J Gen Physiol 2015. [DOI: 10.1085/jgp.1465oia57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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8
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Bryksin AV, Bachman HN, Cooper SW, Balavijayan T, Blackstone RM, Du H, Jenkins JP, Haynes CL, Siemer JL, Fiore VF, Barker TH. One primer to rule them all: universal primer that adds BBa_B0034 ribosomal binding site to any coding standard 10 BioBrick. ACS Synth Biol 2014; 3:956-9. [PMID: 25524097 PMCID: PMC4277749 DOI: 10.1021/sb500047r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Here,
we present a universal, simple, efficient, and reliable way
to add small BioBrick parts to any BioBrick via PCR that is compatible
with BioBrick assembly standard 10. As a proof of principle, we have
designed a universal primer, rbs_B0034, that contains a ribosomal
binding site (RBS; BBa_B0034) and that can be used in PCR to amplify
any coding BioBrick that starts with ATG. We performed test PCRs with
rbs_B0034 on 31 different targets and found it to be 93.6% efficient.
Moreover, when supplemented with a complementary primer, addition
of RBS can be accomplished via whole plasmid site-directed mutagenesis,
thus reducing the time required for further assembly of composite
parts. The described method brings simplicity to the addition of small
parts, such as regulatory elements to existing BioBricks. The final
product of the PCR assembly is indistinguishable from the standard
or 3A BioBrick assembly.
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Affiliation(s)
- Anton V. Bryksin
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Haylee N. Bachman
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
- School of Chemistry & Biochemistry, School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Spencer W. Cooper
- Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Tilak Balavijayan
- Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | | | - Haoli Du
- Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | | | - Casey L. Haynes
- Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jessica L. Siemer
- Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Vincent F. Fiore
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Thomas H. Barker
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
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Barker TH, Dysart MM, Brown AC, Douglas AM, Fiore VF, Russell AG. Synergistic effects of particulate matter and substrate stiffness on epithelial-to-mesenchymal transition. Res Rep Health Eff Inst 2014:3-41. [PMID: 25669020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Abstract
Dysfunctional pulmonary homeostasis and repair, including diseases such as pulmonary fibrosis, chronic obstructive pulmonary disease (COPD*), and tumorigenesis, have been increasing steadily over the past decade, a fact that heavily implicates environmental influences. Several investigations have suggested that the lung "precursor cell"--the alveolar type II (ATII) epithelial cell--is central in the initiation and progression of pulmonary fibrosis. Specifically, ATII cells have been shown (Iwano et al. 2002) to be capable of undergoing an epithelial-to-mesenchymal transition (EMT). EMT, the de-differentiation of an epithelial cell into a mesenchymal cell, has been theorized to increase the number of extracellular matrix (ECM)-secreting mesenchymal cells, perpetuating fibrotic conditions and resulting in increased lung tissue stiffness. In addition, increased exposure to pollution and inhalation of particulate matter (PM) have been shown to be highly correlated with an increased incidence of pulmonary fibrosis. Although both of these events are involved in the progression of pulmonary fibrosis, the relationship between tissue stiffness, exposure to PM, and the initiation and course of EMT remains unclear. The hypothesis of this study was twofold: 1. That alveolar epithelial cells cultured on increasingly stiff substrates become increasingly contractile, leading to enhanced transforming growth factor beta (TGF-β) activation and EMT; and 2. That exposure of alveolar epithelial cells to PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5; also known as fine PM) results in enhanced cell contractility and EMT. Our study focused on the relationship between the micromechanical environment and external environmental stimuli on the phenotype of alveolar epithelial cells. This relationship was explored by first determining how increased tissue stiffness affects the regulation of fibronectin (Fn)-mediated EMT in ATII cells in vitro. We cultured ATII cells on substrates of increasing stiffness and evaluated changes in cell contractility and EMT. We found that stiff, but not soft, Fn substrates were able to induce EMT and that this event depended on a contractile phenotype of the cell and the subsequent activation of TGF-β. In addition, we were able to show that activation or suppression of cell contractility by way of exogenous factors was sufficient to overcome the effect of substrate stiffness. Pulse-chase experiments indicated that the effect on cell contractility is dose- and time-dependent. In response to low levels of TGF-β on soft surfaces, either added exogenously or produced through contraction induced by the stiffness agonist thrombin, cells initiate EMT; on removal of the TGF-β, they revert to an epithelial phenotype. Overall, the results from this first part of our study identified matrix stiffness or cell contractility as critical targets for the control of EMT in fibrotic diseases. For the second part of our study, we wanted to investigate whether exposure to PM2.5, which might have higher toxicity than coarser PM because of its small size and large surface-to-mass ratio, altered the observed stiffness-mediated EMT. Again, we cultured ATII cells on increasingly stiff substrates with or without the addition of three concentrations of PM2.5. We found that exposure to PM2.5 was involved in increased stiffness-mediated EMT, as shown by increases in mesenchymal markers, cell contractility, and TGF-β activation. Most notably, on substrates with an elastic modulus (E) of 8 kilopascals (kPa), a physiologically relevant range for pulmonary fibrosis, the addition of PM2.5 resulted in increased mesenchymal cells and EMT; these were not seen in the absence of the PM2.5. Overall, this study showed that there is a delicate balance between substrate stiffness, TGF-β, and EMT. Furthermore, we showed that exposure to PM2.5 is able to further mediate this interaction. The higher levels of EMT seen with exposure to PM2.5 might have been a result of a positive feedback loop, in which enhanced exposure to PM2.5 through the loss of cell-cell junctions during the initial stages of EMT led to the cells being more susceptible to the effects of surrounding immune cells and inflammatory signals that can further activate TGF-β and drive additional EMT progression. Overall, our work--showing increased cell contractility, TGF-β activation, and EMT in response to substrate stiffness and PM2.5 exposure--highlights the importance of both the micromechanical and biochemical environments in lung disease. These findings suggest that already-fibrotic tissue might be more susceptible to further damage than healthy tissue when exposed to PM2.5.
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Fiore VF, Ju L, Chen Y, Zhu C, Barker TH. Dynamic catch of a Thy-1–α5β1+syndecan-4 trimolecular complex. Nat Commun 2014; 5:4886. [DOI: 10.1038/ncomms5886] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 08/01/2014] [Indexed: 01/09/2023] Open
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Alonas E, Lifland AW, Gudheti M, Vanover D, Jung J, Zurla C, Kirschman J, Fiore VF, Douglas A, Barker TH, Yi H, Wright ER, Crowe JE, Santangelo PJ. Combining single RNA sensitive probes with subdiffraction-limited and live-cell imaging enables the characterization of virus dynamics in cells. ACS Nano 2014; 8:302-15. [PMID: 24351207 PMCID: PMC3906890 DOI: 10.1021/nn405998v] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The creation of fluorescently labeled viruses is currently limited by the length of imaging observation time (e.g., labeling an envelope protein) and the rescue of viral infectivity (e.g., encoding a GFP protein). Using single molecule sensitive RNA hybridization probes delivered to the cytoplasm of infected cells, we were able to isolate individual, infectious, fluorescently labeled human respiratory syncytial virus virions. This was achieved without affecting viral mRNA expression, viral protein expression, or infectivity. Measurements included the characterization of viral proteins and genomic RNA in a single virion using dSTORM, the development of a GFP fusion assay, and the development of a pulse-chase assay for viral RNA production that allowed for the detection of both initial viral RNA and nascent RNA production at designated times postinfection. Live-cell measurements included imaging and characterization of filamentous virion fusion and the quantification of virus replication within the same cell over an eight-hour period. Using probe-labeled viruses, individual viral particles can be characterized at subdiffraction-limited resolution, and viral infections can be quantified in single cells over an entire cycle of replication. The implication of this development is that MTRIP labeling of viral RNA during virus assembly has the potential to become a general methodology for the labeling and study of many important RNA viruses.
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Affiliation(s)
- Eric Alonas
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Aaron W. Lifland
- Vutara, Inc., 615 Arapeen #304, Salt Lake City, Utah 84108, United States
| | - Manasa Gudheti
- Vutara, Inc., 615 Arapeen #304, Salt Lake City, Utah 84108, United States
| | - Daryll Vanover
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Jeenah Jung
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Chiara Zurla
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Jonathan Kirschman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Vincent F. Fiore
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Alison Douglas
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Thomas H. Barker
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Hong Yi
- Robert P. Apkarian Integrated Electron Microscopy Core, College of Medicine, Emory University, Atlanta, Georgia 30322, United States
| | - Elizabeth R. Wright
- Robert P. Apkarian Integrated Electron Microscopy Core, College of Medicine, Emory University, Atlanta, Georgia 30322, United States
- Department of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, 2015 Uppergate Drive, NE, Suite 548, Atlanta, Georgia 30322, United States
| | - James E. Crowe
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Philip J. Santangelo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
- Address correspondence to
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Brown AC, Fiore VF, Sulchek TA, Barker TH. Physical and chemical microenvironmental cues orthogonally control the degree and duration of fibrosis-associated epithelial-to-mesenchymal transitions. J Pathol 2013; 229:25-35. [PMID: 23018598 DOI: 10.1002/path.4114] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 09/05/2012] [Accepted: 09/14/2012] [Indexed: 11/11/2022]
Abstract
Increased tissue stiffness and epithelial-to-mesenchymal transitions (EMTs) are two seemingly discrete hallmarks of fibrotic diseases. Despite recent findings highlighting the influence of tissue mechanical properties on cell phenotype, it remains unclear what role increased tissue stiffness has in the regulation of previously reported fibronectin-mediated EMTs associated with pulmonary fibrosis. Nano-indentation testing of lung interstitial spaces showed that in vivo cell-level Young's moduli increase with the onset of fibrosis from ∼2 to ∼17 kPa. In vitro, we found that stiff, but not soft, fibronectin substrates induce EMT, a response dependent on cell contraction-mediated integrin activation of TGFβ. Activation or suppression of cell contractility with exogenous factors was sufficient to overcome the effect of substrate stiffness. Pulse-chase experiments indicate that the effect of cell contractility is dose- and time-dependent. In response to low levels of TGFβ on soft surfaces, either added exogenously or produced through thrombin-induced contraction, cells will initiate the EMT programme, but upon removal revert to an epithelial phenotype. These results identify matrix stiffness and/or cell contractility as critical targets for novel therapeutics for fibrotic diseases.
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Affiliation(s)
- Ashley C Brown
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332-0535, USA
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Booth AJ, Hadley R, Cornett AM, Dreffs AA, Matthes SA, Tsui JL, Weiss K, Horowitz JC, Fiore VF, Barker TH, Moore BB, Martinez FJ, Niklason LE, White ES. Acellular normal and fibrotic human lung matrices as a culture system for in vitro investigation. Am J Respir Crit Care Med 2012; 186:866-76. [PMID: 22936357 DOI: 10.1164/rccm.201204-0754oc] [Citation(s) in RCA: 445] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
RATIONALE Extracellular matrix (ECM) is a dynamic tissue that contributes to organ integrity and function, and its regulation of cell phenotype is a major aspect of cell biology. However, standard in vitro culture approaches are of unclear physiologic relevance because they do not mimic the compositional, architectural, or distensible nature of a living organ. In the lung, fibroblasts exist in ECM-rich interstitial spaces and are key effectors of lung fibrogenesis. OBJECTIVES To better address how ECM influences fibroblast phenotype in a disease-specific manner, we developed a culture system using acellular human normal and fibrotic lungs. METHODS Decellularization was achieved using treatment with detergents, salts, and DNase. The resultant matrices can be sectioned as uniform slices within which cells were cultured. MEASUREMENTS AND MAIN RESULTS We report that the decellularization process effectively removes cellular and nuclear material while retaining native dimensionality and stiffness of lung tissue. We demonstrate that lung fibroblasts reseeded into acellular lung matrices can be subsequently assayed using conventional protocols; in this manner we show that fibrotic matrices clearly promote transforming growth factor-β-independent myofibroblast differentiation compared with normal matrices. Furthermore, comprehensive analysis of acellular matrix ECM details significant compositional differences between normal and fibrotic lungs, paving the way for further study of novel hypotheses. CONCLUSIONS This methodology is expected to allow investigation of important ECM-based hypotheses in human tissues and permits future scientific exploration in an organ- and disease-specific manner.
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Affiliation(s)
- Adam J Booth
- Division of Pulmonary and Critical Care Medicine, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5642, USA
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Huang X, Yang N, Fiore VF, Barker TH, Sun Y, Morris SW, Ding Q, Thannickal VJ, Zhou Y. Matrix stiffness-induced myofibroblast differentiation is mediated by intrinsic mechanotransduction. Am J Respir Cell Mol Biol 2012; 47:340-8. [PMID: 22461426 DOI: 10.1165/rcmb.2012-0050oc] [Citation(s) in RCA: 351] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The mechanical properties of the extracellular matrix have recently been shown to promote myofibroblast differentiation and lung fibrosis. Mechanisms by which matrix stiffness regulates myofibroblast differentiation are not fully understood. The goal of this study was to determine the intrinsic mechanisms of mechanotransduction in the regulation of matrix stiffness-induced myofibroblast differentiation. A well established polyacrylamide gel system with tunable substrate stiffness was used in this study. Megakaryoblastic leukemia factor-1 (MKL1) nuclear translocation was imaged by confocal immunofluorescent microscopy. The binding of MKL1 to the α-smooth muscle actin (α-SMA) gene promoter was quantified by quantitative chromatin immunoprecipitation assay. Normal human lung fibroblasts responded to matrix stiffening with changes in actin dynamics that favor filamentous actin polymerization. Actin polymerization resulted in nuclear translocation of MKL1, a serum response factor coactivator that plays a central role in regulating the expression of fibrotic genes, including α-SMA, a marker for myofibroblast differentiation. Mouse lung fibroblasts deficient in Mkl1 did not respond to matrix stiffening with increased α-SMA expression, whereas ectopic expression of human MKL1 cDNA restored the ability of Mkl1 null lung fibroblasts to express α-SMA. Furthermore, matrix stiffening promoted production and activation of the small GTPase RhoA, increased Rho kinase (ROCK) activity, and enhanced fibroblast contractility. Inhibition of RhoA/ROCK abrogated stiff matrix-induced actin cytoskeletal reorganization, MKL1 nuclear translocation, and myofibroblast differentiation. This study indicates that actin cytoskeletal remodeling-mediated activation of MKL1 transduces mechanical stimuli from the extracellular matrix to a fibrogenic program that promotes myofibroblast differentiation, suggesting an intrinsic mechanotransduction mechanism.
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Affiliation(s)
- Xiangwei Huang
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Tinsley Harrison Tower 437B, 1900 University Blvd., Birmingham, AL 35294, USA
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Phelps EA, Enemchukwu NO, Fiore VF, Sy JC, Murthy N, Sulchek TA, Barker TH, García AJ. Maleimide cross-linked bioactive PEG hydrogel exhibits improved reaction kinetics and cross-linking for cell encapsulation and in situ delivery. Adv Mater 2012; 24:64-70, 2. [PMID: 22174081 PMCID: PMC3517145 DOI: 10.1002/adma.201103574] [Citation(s) in RCA: 363] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Indexed: 05/20/2023]
Abstract
Engineered polyethylene glycol-maleimide matrices for regenerative medicine exhibit improved reaction efficiency and wider range of Young’s moduli by utilizing maleimide cross-linking chemistry. This hydrogel chemistry is advantageous for cell delivery due to the mild reaction that occurs rapidly enough for in situ delivery, while easily lending itself to “plug-and-play” design variations such as incorporation of enzyme-cleavable cross-links and cell-adhesion peptides.
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Affiliation(s)
- Edward A. Phelps
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Nduka O. Enemchukwu
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Vincent F. Fiore
- Coulter Department of Biomedical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Jay C. Sy
- Coulter Department of Biomedical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Niren Murthy
- Coulter Department of Biomedical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Todd A. Sulchek
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Thomas H. Barker
- Coulter Department of Biomedical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
| | - Andrés J. García
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
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Cha P, Krishnan A, Fiore VF, Vogler EA. Interfacial energetics of protein adsorption from aqueous buffer to surfaces with varying hydrophilicity. Langmuir 2008; 24:2553-2563. [PMID: 18229964 DOI: 10.1021/la703310k] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Adsorption isotherms constructed from time-and-concentration-dependent advancing contact angles thetaa show that the profound biochemical diversity among ten different blood proteins with molecular weight spanning 10-1000 kDa has little discernible effect on the amount adsorbed from aqueous phosphate-buffered saline (PBS) solution after 1 h contact with a particular test surface selected from the full range of observable water wettability (as quantified by PBS adhesion tension tauoa=gammaolv cos thetaoa; where gammaolv is the liquid-vapor interfacial tension and thetaoa is the advancing PBS contact angle). The maximum advancing spreading pressure, Pimaxa, determined from adsorption isotherms decreases systematically with tauoa for methyl-terminated self-assembled monolayers (CH3 SAM, tauo=-15 mN/m), polystyrene spun-coated onto electronic-grade SiOx wafers (PS, tauo=7.2 mN/m), aminopropyltriethoxysilane-treated SiOx surfaces (APTES, tauo = 42 mN/m), and fully water wettable SiOx (tauo=72 mN/m). Likewise, the apparent Gibbs' surface excess [Gammasl-Gammasv], which measures the difference in the amount of protein adsorbed Gamma (mol/cm2) at solid-vapor (SV) and solid-liquid (SL) interfaces, decreases with tauo from maximal values measured on the CH3 SAM surface through zero (no protein adsorption in excess of bulk solution concentration) near tauo=30 mN/m (thetaa=65 degrees). These latter results corroborate the conclusion drawn from independent studies that water is too strongly bound to surfaces with tauo>or=30 mN/m to be displaced by adsorbing protein and that, as a consequence, protein does not accumulate within the interfacial region of such surfaces at concentrations exceeding that of bulk solution ([Gammasl-Gammasv]=0 at tauo=30 mN/m). Results are collectively interpreted to mean that water controls protein adsorption to surfaces and that the mechanism of protein adsorption can be understood from this perspective for a diverse set of proteins with very different amino acid compositions.
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Affiliation(s)
- Paul Cha
- Department of Materials Science, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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