title: Serum-induced keratinization processes in an immortalized human meibomian gland epithelial cell line.
abstract: OBJECTIVE
  The aim of this study was to evaluate a human meibomian gland epithelial cell line (HMGEC) as a model for meibomian gland (patho)physiology in vitro.
  
  
  METHODS
  HMGEC were cultured in the absence or presence of serum. Sudan III lipid staining, ultrastructural analysis and lipidomic analyses were performed. Impedance sensing, desmoplakin 1/2 mRNA and cytokeratin (CK) 1, 5, 6, 14 levels were evaluated. Serum containing medium supplemented with higher serum, glucose, an omega-3 lipid cocktail, eicosapentaenoic acid or sebomed medium were investigated for lipid accumulation and ultrastructural morphology.
  
  
  RESULTS
  Lipid droplet accumulation in HMGEC was induced by serum containing media after 1 day, but decreased over time. Cultivation in serum induced desmosome and cytokeratin filament formation. Desmoplakin 1/2 gene levels were significantly upregulated after 1d of serum treatment. Furthermore, the normalized impedance increased significantly. Lipidome analysis revealed high levels of phospholipids (over 50%), but very low levels of wax ester and cholesteryl esters (under 1%). Stimulation with eicosapentaenoic acid increased lipid accumulation after one day.
  
  
  CONCLUSIONS
  Serum treatment of HMGEC caused lipid droplet formation to some extent but also induced keratinization. The cells did not produce typical meibum lipids under these growth conditions. HMGEC are well suited to study (hyper)keratinization processes of meibomian gland epithelial cells in vitro.
authors.affiliation: Department of Anatomy II, Friedrich-Alexander-University Erlangen Nürnberg, Erlangen, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hampel
authors.affiliation: Department of Anatomy II, Friedrich-Alexander-University Erlangen Nürnberg, Erlangen, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Schröder
authors.affiliation: Illawara Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia.
authors.forename: Todd
authors.initials: T
authors.lastname: Mitchell
authors.affiliation: Illawara Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Brown
authors.affiliation: Illawara Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia.
authors.forename: Peta
authors.initials: P
authors.lastname: Snikeris
authors.affiliation: Department of Anatomy II, Friedrich-Alexander-University Erlangen Nürnberg, Erlangen, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Garreis
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Carolina
authors.initials: C
authors.lastname: Kunnen
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Willcox
authors.affiliation: Department of Anatomy II, Friedrich-Alexander-University Erlangen Nürnberg, Erlangen, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Paulsen
mesh_terms: D015153:Blotting, Western; D002461:Cell Line, Transformed; D003470:Culture Media / Q000494:pharmacology; D003896:Desmosomes / Q000187:drug effects / Q000378:metabolism; D017097:Electric Impedance; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007633:Keratins / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects; D008537:Meibomian Glands / Q000166:cytology*; D044967:Serum / Q000378:metabolism*; D013194:Staining and Labeling; D013997:Time Factors
chemical_list: D003470:Culture Media; D007633:Keratins; D005947:Glucose