Dataset Information

Modification of human prekeratin during epidermal differentiation.

ABSTRACT: The polypeptide-chain components of human epidermal prekeratin and keratin were analysed by high-resolution SDS (sodium dodecyl sulphate)/polyacrylamide-gradient-gel electrophoresis. Size heterogeneity existed amongst prekeratin components and at least ten polypeptides, in the molecular-weight range 46,000-70,000, were observed in 0.1 M-citric acid/sodium citrate buffer (pH 2.65) extracts of scale epidermis. Prekeratin from scalp pilosebaceous ducts was identical with that from the contiguous epidermis, and no prekeratin was found in extracts of scale dermis. Prekeratin from plantar epidermis contained additional polypeptide chains, but only slight anatomical variation existed between the non-callus sites examined. Keratin differed from prekeratin in at least two major respects: (a) many major components did not co-electrophorese on high-resolution SDS/polyacrylamide slab gels, and (b) keratin, but not prekeratin, required denaturing and reducing conditions for extraction. Keratin extracted from scale epidermis after complete removal of prekeratin was identical with forearm stratum-corneum keratin. Palmar and plantar keratin contained additional polypeptide chains and had a different size distribution compared with forearm and scalp keratin components. Modification of prekeratin components to produce the keratin polypeptide profile occurred during epidermal differentiation, and these changes appeared to take place in the granular-layer region of the epidermis.

SUBMITTER: Bowden PE

PROVIDER: S-EPMC1163344 | biostudies-other | 1981 Oct

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:BACKGROUND: Nodular melanoma is one of the most life threatening tumors with still poor therapeutic outcome. Similarly to other tumors, permissive microenvironment is essential for melanoma progression. Features of this microenvironment are arising from molecular crosstalk between the melanoma cells (MC) and the surrounding cell populations in the context of skin tissue. Here, we study the effect of melanoma cells on human primary keratinocytes (HPK). Presence of MC is as an important modulator of the tumor microenvironment and we compare it to the effect of nonmalignant lowly differentiated cells also originating from neural crest (NCSC). METHODS: Comparative morphometrical and immunohistochemical analysis of epidermis surrounding nodular melanoma (n?=?100) was performed. Data were compared to results of transcriptome profiling of in vitro models, in which HPK were co-cultured with MC, normal human melanocytes, and NCSC, respectively. Differentially expressed candidate genes were verified by RT-qPCR. Biological activity of candidate proteins was assessed on cultured HPK. RESULTS: Epidermis surrounding nodular melanoma exhibits hyperplastic features in 90% of cases. This hyperplastic region exhibits aberrant suprabasal expression of keratin 14 accompanied by loss of keratin 10. We observe that MC and NCSC are able to increase expression of keratins 8, 14, 19, and vimentin in the co-cultured HPK. This in vitro finding partially correlates with pseudoepitheliomatous hyperplasia observed in melanoma biopsies. We provide evidence of FGF-2, CXCL-1, IL-8, and VEGF-A participation in the activity of melanoma cells on keratinocytes. CONCLUSION: We conclude that the MC are able to influence locally the differentiation pattern of keratinocytes in vivo as well as in vitro. This interaction further highlights the role of intercellular interactions in melanoma. The reciprocal role of activated keratinocytes on biology of melanoma cells shall be verified in the future.

Project description:Human epidermal stem cells initiate terminal differentiation when spreading is restricted on ECM-coated micropatterned islands, soft hydrogels or hydrogel-nanoparticle composites with high nanoparticle spacing. The effect of substrate topography, however, is incompletely understood. To explore this, primary human keratinocytes enriched for stem cells were seeded on a topographical library with over 2000 different topographies in the micrometre range. Twenty-four hours later the proportion of cells expressing the differentiation marker transglutaminase-1 was determined by high content imaging. As predicted, topographies that prevented spreading promoted differentiation. However, we also identified topographies that supported differentiation of highly spread cells. Topographies supporting differentiation of spread cells were more irregular than those supporting differentiation of round cells. Low topography coverage promoted differentiation of spread cells, whereas high coverage promoted differentiation of round cells. Based on these observations we fabricated a topography in 6-well plate format that supported differentiation of spread cells, enabling us to examine cell responses at higher resolution. We found that differentiated spread cells did not assemble significant numbers of hemidesmosomes, focal adhesions, adherens junctions, desmosomes or tight junctions. They did, however, organise the actin cytoskeleton in response to the topographies. Rho kinase inhibition and blebbistatin treatment blocked the differentiation of spread cells, whereas SRF inhibition did not. These observations suggest a potential role for actin polymerization and actomyosin contraction in the topography-induced differentiation of spread cells. STATEMENT OF SIGNIFICANCE: The epidermis is the outer covering of the skin. It is formed by layers of cells called keratinocytes. The basal cell layer contains stem cells, which divide to replace cells in the outermost layers that are lost through a process known as differentiation. In this manuscript we have developed surfaces that promote the differentiation of epidermal stem cells in order to understand the signals that control differentiation. The experimental tools we have developed have the potential to help us to devise new treatments that control diseases such as psoriasis and eczema in which epidermal stem cell proliferation and differentiation are disturbed.

Dataset Information

Modification of human prekeratin during epidermal differentiation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets