title: Picea mariana polyphenolic extract inhibits phlogogenic mediators produced by TNF-α-activated psoriatic keratinocytes: Impact on NF-κB pathway.
abstract: BACKGROUND
  Picea mariana ((Miller) Britton, Sterns, and Poggenburg; Pinaceae) bark has been traditionally used by North American natives for treating topical inflammations. It has been also suggested to improve various inflammatory skin disorders like Psoriasis vulgaris. Extracts from this bark storage protein contain polyphenolic compounds which have well-known antiinflammatory activities. Based on the capacity of polyphenolic compounds to modulate functions of normal human keratinocytes, this study was set up to decipher the mechanisms of action of a chemically characterized polyphenolic extract from Picea mariana bark (BS-EAcf) on lesional keratinocytes of skin with psoriasis vulgaris, a disease driven by the immune system in which TNF-α plays a significant role.
  
  
  METHODS
  BS-EAcf corresponds to the ethyl acetate soluble fraction from the hot water extract of Picea mariana bark. BS-EAcf effects were evaluated in normal human (NHK) and psoriatic (PK) keratinocytes stimulated by TNF-α. Cell viability was assessed by lactate deshydrogenase release and propidium iodide (PI) staining. The mechanisms of action of BS-EAcf in keratinocytes were investigated by flow cytometry, ELISAs, RT-PCR and western blot analyses.
  
  
  RESULTS
  PK exhibited a higher response to TNF-α than NHK regarding the ICAM-1 expression and the production of NO, IL-6, IL-8, fractalkine and PGE2, whereas BS-EAcf significantly inhibited this TNF-α-induced increase at concentrations without causing keratinocyte toxicity. Additionally, this extract significantly inhibited the TNF-α-induced release of elafin and VEGF by PK and NHK. Since TNF-α activation of most of these factors is dependent on the NF-κB pathway, this latter was studied in TNF-α-activated PK. BS-EAcf inhibited the TNF-α-induced phosphorylation and degradation of total IκBα as well as phosphorylation of NF-κB p65.
  
  
  CONCLUSIONS
  The ethyl acetate fraction from Picea mariana bark extract showed inhibitory effects of cytokines, chemokines, adhesion molecules, nitric oxide and prostaglandins produced by keratinocytes under TNF-α activation through down-regulating the NF-κB pathway. This study demontrated that this extract could be a potential antiinflammatory agent capable of improving psoriatic skin.
authors.affiliation: Centre de Recherche en Rhumatologie et Immunologie, Boulevard Laurier, Centre de Recherche du CHU de Québec, Department of Medicine, Université Laval, Québec, Canada; Centre de Recherche sur le Bois, Département des sciences du bois et de la forêt, Faculté de foresterie et géomatique, Université Laval, Canada; Laboratoire d'Organogénèse Expérimentale (LOEX), Centre de Recherche du CHU de Québec, Faculté de Pharmacie, Université Laval, Canada.
authors.forename: Martha-Estrella
authors.initials: ME
authors.lastname: García-Pérez
authors.affiliation: Centre de Recherche en Rhumatologie et Immunologie, Boulevard Laurier, Centre de Recherche du CHU de Québec, Department of Medicine, Université Laval, Québec, Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Allaeys
authors.affiliation: Centre de Recherche en Rhumatologie et Immunologie, Boulevard Laurier, Centre de Recherche du CHU de Québec, Department of Medicine, Université Laval, Québec, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rusu
authors.affiliation: Laboratoire d'Organogénèse Expérimentale (LOEX), Centre de Recherche du CHU de Québec, Faculté de Pharmacie, Université Laval, Canada.
authors.forename: Roxane
authors.initials: R
authors.lastname: Pouliot
authors.affiliation: Centre de Recherche sur le Bois, Département des sciences du bois et de la forêt, Faculté de foresterie et géomatique, Université Laval, Canada.
authors.forename: Tatjana Stevanovic
authors.initials: TS
authors.lastname: Janezic
authors.affiliation: Centre de Recherche en Rhumatologie et Immunologie, Boulevard Laurier, Centre de Recherche du CHU de Québec, Department of Medicine, Université Laval, Québec, Canada. Electronic address: Patrice.Poubelle@crchul.ulaval.ca.
authors.forename: Patrice E
authors.initials: PE
authors.lastname: Poubelle
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D053492:Elafin / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D028222:Picea / Q000737:chemistry*; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011565:Psoriasis / Q000378:metabolism* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D053492:Elafin; D016328:NF-kappa B; C506806:PI3 protein, human; D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase
keywords: Cytokines; Inflammation; Keratinocytes; Polyphenols; Prostaglandins; Psoriasis