title: Single-walled carbon nanotubes increase pandemic influenza A H1N1 virus infectivity of lung epithelial cells.
abstract: BACKGROUND
  Airborne exposure to nanomaterials from unintended occupational or environmental exposures or as a consequence of product use may lead to adverse health effects. Numerous studies have focused on single-walled carbon nanotubes (SWCNTs) and their ability to cause pulmonary injury related to fibrosis, and cancer; however few studies have addressed their impact on infectious agents, particularly viruses that are known for causing severe disease. Here we have demonstrated the ability of pristine SWCNTs of diverse electronic structure to increase the susceptibility of small airway epithelial cells (SAEC) to pandemic influenza A H1N1 infection and discerned potential mechanisms of action driving this response.
  
  
  METHODS
  Small airway epithelial cells (SAEC) were exposed to three types of SWCNTs with varying electronic structure (SG65, SG76, CG200) followed by infection with A/Mexico/4108/2009 (pH1N1). Cells were then assayed for viral infectivity by immunofluorescence and viral titers. We quantified mRNA and protein levels of targets involved in inflammation and anti-viral activity (INFβ1, IL-8, RANTES/CCL5, IFIT2, IFIT3, ST3GAL4, ST6GAL1, IL-10), localized sialic acid receptors, and assessed mitochondrial function. Hyperspectral imaging analysis was performed to map the SWCNTs and virus particles in fixed SAEC preparations. We additionally performed characterization analysis to monitor SWCNT aggregate size and structure under biological conditions using dynamic light scattering (DLS), static light scattering (SLS).
  
  
  RESULTS
  Based on data from viral titer and immunofluorescence assays, we report that pre-treatment of SAEC with SWCNTs significantly enhances viral infectivity that is not dependent on SWCNT electronic structure and aggregate size within the range of 106 nm - 243 nm. We further provide evidence to support that this noted effect on infectivity is not likely due to direct interaction of the virus and nanoparticles, but rather a combination of suppression of pro-inflammatory (RANTES) and anti-viral (IFIT2, IFIT3) gene/protein expression, impaired mitochondrial function and modulation of viral receptors by SWCNTs.
  
  
  CONCLUSIONS
  Results of this work reveal the potential for SWCNTs to increase susceptibility to viral infections as a mechanism of adverse effect. These data highlight the importance of investigating the ability of carbon-nanomaterials to modulate the immune system, including impacts on anti-viral mechanisms in lung cells, thereby increasing susceptibility to infectious agents.
authors.affiliation: Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida, 2187 Mowry Road, Box 110885, Gainesville, FL, 32611, USA. pallabsanpui@gmail.com.
authors.forename: Pallab
authors.initials: P
authors.lastname: Sanpui
authors.affiliation: Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida, 2187 Mowry Road, Box 110885, Gainesville, FL, 32611, USA. xiaozhengxjtu@gmail.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida, 2187 Mowry Road, Box 110885, Gainesville, FL, 32611, USA. jloeb@phhp.ufl.edu.
authors.forename: Julia C
authors.initials: JC
authors.lastname: Loeb
authors.affiliation: Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida, 2187 Mowry Road, Box 110885, Gainesville, FL, 32611, USA. jbisesi@phhp.ufl.edu.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Bisesi
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 E. Dean Keeton Street, Austin, TX, 78712, USA. iftheker04@gmail.com.
authors.forename: Iftheker A
authors.initials: IA
authors.lastname: Khan
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 E. Dean Keeton Street, Austin, TX, 78712, USA. rnabiul@gmail.com.
authors.forename: A R M Nabiul
authors.initials: AR
authors.lastname: Afrooz
authors.affiliation: Department of Civil and Environmental Engineering, Nicholas School of the Environment, and Center for the Environmental Implications of NanoTechnology, Duke University, 121 Hudson Hall, Box 90287, Durham, NC, 27708, USA. keiraliu125@gmail.com.
authors.forename: Keira
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Civil and Environmental Engineering, Nicholas School of the Environment, and Center for the Environmental Implications of NanoTechnology, Duke University, 121 Hudson Hall, Box 90287, Durham, NC, 27708, USA. appala.badireddy@duke.edu.
authors.forename: Appala Raju
authors.initials: AR
authors.lastname: Badireddy
authors.affiliation: Department of Civil and Environmental Engineering, Nicholas School of the Environment, and Center for the Environmental Implications of NanoTechnology, Duke University, 121 Hudson Hall, Box 90287, Durham, NC, 27708, USA. wiesner@duke.edu.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wiesner
authors.affiliation: Department of Civil and Environmental Engineering, Nicholas School of the Environment, and Center for the Environmental Implications of NanoTechnology, Duke University, 121 Hudson Hall, Box 90287, Durham, NC, 27708, USA. lee.ferguson@duke.edu.
authors.forename: P Lee
authors.initials: PL
authors.lastname: Ferguson
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 E. Dean Keeton Street, Austin, TX, 78712, USA. navid.saleh@utexas.edu.
authors.forename: Navid B
authors.initials: NB
authors.lastname: Saleh
authors.affiliation: Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida, 2187 Mowry Road, Box 110885, Gainesville, FL, 32611, USA. jlednicky@phhp.ufl.edu.
authors.forename: John A
authors.initials: JA
authors.lastname: Lednicky
authors.affiliation: Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida, 2187 Mowry Road, Box 110885, Gainesville, FL, 32611, USA. sabo@phhp.ufl.edu.
authors.forename: Tara
authors.initials: T
authors.lastname: Sabo-Attwood
mesh_terms: D000393:Air Pollutants / Q000737:chemistry / Q000633:toxicity*; D051017:Apoptosis Regulatory Proteins; D001980:Bronchi / Q000166:cytology / Q000276:immunology / Q000821:virology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D018946:Chemokine CCL5 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects*; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects / Q000276:immunology / Q000472:pathogenicity*; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D010316:Particle Size; D011506:Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D020545:Respiratory Mucosa / Q000166:cytology / Q000276:immunology / Q000821:virology*; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D051017:Apoptosis Regulatory Proteins; C483024:CCL5 protein, human; D018946:Chemokine CCL5; C484289:IFIT2 protein, human; C116468:IFIT3 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D037742:Nanotubes, Carbon; D011506:Proteins; D016601:RNA-Binding Proteins