title: Effect of desiccating environmental stress versus systemic muscarinic AChR blockade on dry eye immunopathogenesis.
abstract: OBJECTIVE
  A majority of experimental data on dry eye disease (DED) immunopathogenesis have been derived from a murine model of DED that combines desiccating environmental stress with systemic muscarinic acetylcholine receptor (mAChR) inhibition. However, to our knowledge the effects of pharmacologic mAChR blockade on the pathogenesis of experimental DED have not been evaluated systemically. The purpose of our study was to investigate the differential effects of desiccating environmental stress and mAChR inhibition on the pathogenesis of DED.
  
  
  METHODS
  DED was induced in female C57BL/6 mice by exposure to a desiccating environment in the controlled-environment chamber or to systemic scopolamine, or by performing extraorbital lacrimal gland excision. Clinical disease was assessed using corneal fluorescein staining (CFS) and the cotton thread test (CTT). Corneal CD11b(+) and conjunctival CD3(+) T-cell infiltration were evaluated by flow cytometry. T-cells from draining cervical lymph nodes (CLN) and distant inguinal lymph nodes (ILN) were analyzed for Th1, Th2, Th17, and Treg responses by flow cytometry and ELISA.
  
  
  RESULTS
  Desiccating environmental stress and systemic mAChR blockade induced similar clinical signs of DED. However, desiccating environmental stress imparted higher conjunctival CD3(+) T-cell infiltration, and greater Th17-cell activity and Treg dysfunction than mAChR blockade, while mAChR blockade decreased tear secretion to a greater extent than desiccating environmental stress. Systemic mAChR blockade attenuated Th17 activity and enhanced Th2 and Treg responses without affecting Th1 activity.
  
  
  CONCLUSIONS
  In vivo inhibition of mAChRs variably affects CD4(+) T-cell subsets, and desiccating environmental stress and systemic mAChR blockade induce DED through different primary pathogenic mechanisms.
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Yihe
authors.initials: Y
authors.lastname: Chen
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Chauhan
authors.forename: Hyun Soo
authors.initials: HS
authors.lastname: Lee
authors.forename: William
authors.initials: W
authors.lastname: Stevenson
authors.forename: Chris S
authors.initials: CS
authors.lastname: Schaumburg
authors.forename: Zahra
authors.initials: Z
authors.lastname: Sadrai
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Saban
authors.forename: Shilpa
authors.initials: S
authors.lastname: Kodati
authors.forename: Michael E
authors.initials: ME
authors.lastname: Stern
authors.forename: Reza
authors.initials: R
authors.lastname: Dana
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D015352:Dry Eye Syndromes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D007765:Lacrimal Apparatus / Q000601:surgery; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D011976:Receptors, Muscarinic / Q000502:physiology; D012601:Scopolamine / Q000494:pharmacology*; D013312:Stress, Physiological; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
chemical_list: D016207:Cytokines; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D012601:Scopolamine