Keratin mutations of epidermolysis bullosa simplex alter the kinetics of stress response to osmotic shock.
The intermediate filament cytoskeleton is thought to confer physical resilience on tissue cells, on the basis of extrapolations from the phenotype of cell fragility that results from mutations in skin keratins. There is a need for functional cell assays in which the impact of stress on intermediate filaments can be induced and analyzed. Using osmotic shock, we have induced cytoskeleton changes that suggest protective functions for actin and intermediate filament systems. Induction of the resulting stress response has been monitored in keratinocyte cells lines carrying K5 or K14 mutations, which are associated with varying severity of epidermolysis bullosa simplex. Cells with severe mutations were more sensitive to osmotic stress and took longer to recover from it. Their stress-activated response pathways were induced faster, as seen by early activation of JNK, ATF-2 and c-Jun. We demonstrate that the speed of a cell's response to hypotonic stress, by activation of the SAPK/JNK pathway, is correlated with the clinical severity of the mutation carried. The response to hypo-osmotic shock constitutes a discriminating stress assay to distinguish between the effects of different keratin mutations and is a potentially valuable tool in developing therapeutic strategies for keratin-based skin fragility disorders.
D'Alessandro
Mariella
M
Cancer Research UK Cell Structure Research Group, University of Dundee School of Life Sciences, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, UK.
Russell
David
D
Morley
Susan M
SM
Davies
Anthony M
AM
Lane
E Birgitte
EB
D008841:Actin Cytoskeleton / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D051698:Activating Transcription Factor 2; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D004817:Epidermis / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D016110:Epidermolysis Bullosa Simplex / Q000201:enzymology* / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D007382:Intermediate Filaments / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D015603:Keratinocytes / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D007633:Keratins / Q000172:deficiency* / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009997:Osmotic Pressure; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D013312:Stress, Physiological / Q000201:enzymology / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism
C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D017362:Cyclic AMP Response Element-Binding Protein; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D007633:Keratins; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases