Dysplastic oral leukoplakia is molecularly distinct from leukoplakia without dysplasia
ORAL DISEASES
Authors: Farah, Camile S.; Fox, Simon A.
Abstract
Objective The molecular mechanisms underlying the development of dysplasia in leukoplakia are unknown. We used RNA sequencing to examine the molecular and biological pathway differences in oral leukoplakia with and without oral epithelial dysplasia. Materials and Methods Excisional biopsy specimens (25) were taken from 24 patients with oral leukoplakia diagnosed histopathologically as either oral epithelial dysplasia (13) or epithelial hyperplasia and keratosis without dysplasia (12). Transcriptome analysis used RNA sequencing, differential expression and hierarchical clustering. Biological signalling was examined by gene ontology, pathway and protein-protein interaction analysis. Results Differential expression analysis showed distinction between the two groups identifying 47 genes as altered in leukoplakia with dysplasia, including SAA1, SAA2, KRT31, KRT37, KRT76, ROBO2, DNAJB5 and DNAJA4. Using hierarchical clustering, dysplastic leukoplakia readily segregated from leukoplakia without dysplasia. Pathway and ontology enrichment analysis provided evidence that downregulation of extracellular matrix (ECM) pathways was a feature of dysplastic lesions. Conclusion Our results suggest that there are detectable changes in the molecular profile of oral leukoplakia exhibiting dysplasia including downregulated ECM as a distinguishing feature of dysplastic lesions. This suggests that reactive changes in stroma may be an early manifestation of dysplastic development. Our study also demonstrates the feasibility of detecting such molecular changes in oral leukoplakia, providing avenues for further investigation of molecular mechanisms of oral dysplasia.
Identification of the C-terminal tail domain of AHF/trichohyalin as the critical site for modulation of the keratin filamentous meshwork in the keratinocyte
JOURNAL OF DERMATOLOGICAL SCIENCE
Authors: Takase, Takahisa; Hirai, Yohei
Abstract
Background: AHF/trichohyalin is a large structural protein abundant in the inner root sheath (IRS) of anagenic hair follicles, which has been thought to mediate the keratin filamentous assembly. However, its functional mechanism is largely unknown. Objective: This study aimed at the identification of the key domain in AHF for keratin association and the establishment of a plausible mechanism for the modulation of the keratin meshwork. Methods: Several keratinocyte cell lines were introduced with the full length or several mutants of AHF, together with IRS-specific keratin krt31, and the profile of the AHF granules and the cellular behaviors were carefully analyzed. Results: Full length of AHF formed small round granules that clearly bound to and aligned on the exogenous keratin filaments in the keratinocytes, severely affected cellular growth, mobility and shape. Intriguingly, the removal of only 6 amino acids around the C-terminal tail of AHF resulted not only in the complete loss of its keratin adherent ability but also in a dramatic enlargement of the granules. Conclusion: We propose a model for cytoskeletal modulation in the IRS of anagenic hair follicles: AHF latches onto the keratin bundles by its C-terminus and rearranges the keratin meshwork by intrinsic cohesive activity for the granule formation. (C) 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.