title: Increased filaggrin-metabolizing enzyme activity in atopic skin: a pilot study using a canine model of atopic dermatitis.
abstract: BACKGROUND
  Filaggrin (FLG) and its metabolites are essential for skin barrier function and hydration of the stratum corneum. Alteration of the FLG metabolism could be the basis for an abnormal skin barrier in allergic dogs.
  
  
  OBJECTIVE
  To investigate the expression and distribution of calpain-1, caspase-14, furin and matriptase, four enzymes involved in FLG metabolism, in the skin of atopic and healthy beagles.
  
  
  METHODS
  Skin biopsies were collected from four healthy and four atopic beagles before and after allergen exposure. The dogs were challenged for three consecutive days to mimic an acute exposure, or once weekly to mimic a chronic exposure to allergens. Skin biopsies were taken on days 0 (nonlesional), 3 and 10 in the "acute" model and on days 0 (nonlesional), 14 and 28 in the "chronic" model. Four healthy dogs were used as controls. Indirect immunofluorescence was used to analyse the distribution and the expression of FLG enzymes in a semi-quantitative manner. Five consecutive pictures/section were taken and the intensity analysed tracing the epidermis and using ImageJ on the traced areas. The enzymes' expression was compared between healthy and atopic nonlesional skin (Day 0) and over time in each group.
  
  
  RESULTS
  All enzymes were expressed in all layers of the epidermis. A significantly higher expression of calpain-1 (P = 0.028), caspase 14 (P = 0.028) and matriptase (P = 0.028) was evident in atopic compared to control dogs on Day 0. No differences over time were seen for any enzyme analysed.
  
  
  CONCLUSIONS
  This preliminary study suggests an abnormal catabolism of FLG in canine atopic skin.
authors.affiliation: Clinica Veterinaria San Siro, via Lampugnano 99, Milano, 20151, Italy.
authors.forename: Natalia
authors.initials: N
authors.lastname: Fanton
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave., Gainesville, FL, 32610, USA.
authors.forename: Domenico
authors.initials: D
authors.lastname: Santoro
authors.affiliation: Clinica Veterinaria San Siro, via Lampugnano 99, Milano, 20151, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Cornegliani
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave., Gainesville, FL, 32610, USA.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Marsella
mesh_terms: D000818:Animals; D002154:Calpain / Q000378:metabolism; D016022:Case-Control Studies; D053456:Caspase 14 / Q000378:metabolism; D003876:Dermatitis, Atopic / Q000201:enzymology / Q000378:metabolism / Q000662:veterinary*; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000201:enzymology* / Q000378:metabolism; D004285:Dogs; D005260:Female; D000091344:Filaggrin Proteins; D045683:Furin / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D008297:Male; D010865:Pilot Projects; D012697:Serine Endopeptidases / Q000378:metabolism; D012867:Skin / Q000201:enzymology / Q000378:metabolism
chemical_list: D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D012697:Serine Endopeptidases; C485595:matriptase; D045683:Furin; D002154:Calpain; D053456:Caspase 14