Induction of p38, tumour necrosis factor-α and RANTES by mechanical stretching of keratinocytes expressing mutant keratin 10R156H.
BACKGROUND
Epidermolytic hyperkeratosis (bullous congenital ichthyosiform erythroderma), characterized by ichthyotic, rippled hyperkeratosis, erythroderma and skin blistering, is a rare autosomal dominant disease caused by mutations in keratin 1 or keratin 10 (K10) genes. A severe phenotype is caused by a missense mutation in a highly conserved arginine residue at position 156 (R156) in K10.


OBJECTIVE
To analyse molecular pathomechanisms of hyperproliferation and hyperkeratosis, we investigated the defects in mechanosensation and mechanotransduction in keratinocytes carrying the K10(R156H) mutation.


METHODS
Differentiated primary human keratinocytes infected with lentiviral vectors carrying wild-type K10 (K10(wt)) or mutated K10(R156H) were subjected to 20% isoaxial stretch. Cellular fragility and mechanosensation were studied by analysis of mitogen-activated protein kinase activation and cytokine release.


RESULTS
Cultured keratinocytes expressing K10(R156H) showed keratin aggregate formation at the cell periphery, whereas the filament network in K10(wt) cells was normal. Under stretching conditions K10(R156H) keratinocytes exhibited about a twofold higher level of filament collapse compared with steady state. In stretched K10(R156H) cells, higher p38 activation, higher release of tumour necrosis factor-α and RANTES but reduced interleukin-1β secretion compared with K10(wt) cells was observed.


CONCLUSIONS
These results demonstrate that the R156H mutation in K10 destabilizes the keratin intermediate filament network and affects stress signalling and inflammatory responses to mechanical stretch in differentiated cultured keratinocytes.
Obarzanek-Fojt
M
M
Service of Dermatology and Venereology, CHUV Lausanne, CH-1011 Lausanne, Switzerland.
Favre
B
B
Huber
M
M
Ryser
S
S
Moodycliffe
A M
AM
Wipff
P-J
PJ
Hinz
B
B
Hohl
D
D
D015153:Blotting, Western; D002478:Cells, Cultured; D018946:Chemokine CCL5 / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D017488:Hyperkeratosis, Epidermolytic / Q000235:genetics / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D053550:Keratin-10 / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D015603:Keratinocytes / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism; D013314:Stress, Mechanical; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D018946:Chemokine CCL5; D053583:Interleukin-1beta; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D053550:Keratin-10; D048051:p38 Mitogen-Activated Protein Kinases