SMAD inhibition attenuates epithelial to mesenchymal transition by primary keratinocytes in vitro.
Epithelial to mesenchymal transition (EMT) is a process whereby epithelial cells undergo transition to a mesenchymal phenotype and contribute directly to fibrotic disease. Recent studies support a role for EMT in cutaneous fibrotic diseases including scleroderma and hypertrophic scarring, although there is limited data on the cytokines and signalling mechanisms regulating cutaneous EMT. We investigated the ability of TGF-β and TNF-α, both overexpressed in cutaneous scleroderma and central mediators of EMT in other epithelial cell types, to induce EMT in primary keratinocytes and studied the signalling mechanisms regulating this process. TGF-β induced EMT in normal human epidermal keratinocytes (NHEK cells), and this process was enhanced by TNF-α. EMT was characterised by changes in morphology, proteome (down-regulation of E-cadherin and Zo-1 and up-regulation of vimentin and fibronectin), MMP secretion and COL1α1 mRNA expression. TGF-β and TNF-α in combination activated SMAD and p38 signalling in NHEK cells. P38 inhibition with SB203580 partially attenuated EMT, whereas SMAD inhibition using SB431542 significantly inhibited EMT and also reversed established EMT. These data highlight the retained plasticity of adult keratinocytes and support further studies of EMT in clinically relevant in vivo models of cutaneous fibrosis and investigation of SMAD inhibition as a potential therapeutic intervention.
Centre For Infection and Immunity, Queen's University Belfast, Belfast, UK.
Donal
D
O'Kane
Megan V
MV
Jackson
Adrien
A
Kissenpfennig
Shaun
S
Spence
Lindsay
L
Damkat-Thomas
Julia P
JP
Tolland
Anita E
AE
Smyth
Christopher P
CP
Denton
J
J
Stuart Elborn
Daniel F
DF
McAuley
Cecilia M
CM
O'Kane
D001549:Benzamides / Q000737:chemistry; D003094:Collagen / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004149:Dioxoles / Q000737:chemistry; D015536:Down-Regulation; D000078404:Epidermal Cells; D058750:Epithelial-Mesenchymal Transition; D005353:Fibronectins / Q000378:metabolism; D005355:Fibrosis / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology*; D020782:Matrix Metalloproteinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D051785:Smad Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D016207:Cytokines; D004149:Dioxoles; D005353:Fibronectins; D011994:Recombinant Proteins; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D014746:Vimentin; D003094:Collagen; D048051:p38 Mitogen-Activated Protein Kinases; D020782:Matrix Metalloproteinases
epithelial to mesenchymal transition; keratinocyte; transforming growth factor-β; tumor necrosis factor-α