- Klíčová slova
- gen p63,
- MeSH
- buněčná diferenciace MeSH
- buněčné dělení MeSH
- epidermis * embryologie fyziologie MeSH
- geny nádorové MeSH
- keratinocyty MeSH
- kmenové buňky * fyziologie patologie MeSH
- lidé MeSH
- mezibuněčné signální peptidy a proteiny MeSH
- nika kmenových buněk MeSH
- signální transdukce MeSH
- vlasový folikul embryologie MeSH
- Check Tag
- lidé MeSH
Two theories address the origin of repeating patterns, such as hair follicles, limb digits, and intestinal villi, during development. The Turing reaction-diffusion system posits that interacting diffusible signals produced by static cells first define a prepattern that then induces cell rearrangements to produce an anatomical structure. The second theory, that of mesenchymal self-organisation, proposes that mobile cells can form periodic patterns of cell aggregates directly, without reference to any prepattern. Early hair follicle development is characterised by the rapid appearance of periodic arrangements of altered gene expression in the epidermis and prominent clustering of the adjacent dermal mesenchymal cells. We assess the contributions and interplay between reaction-diffusion and mesenchymal self-organisation processes in hair follicle patterning, identifying a network of fibroblast growth factor (FGF), wingless-related integration site (WNT), and bone morphogenetic protein (BMP) signalling interactions capable of spontaneously producing a periodic pattern. Using time-lapse imaging, we find that mesenchymal cell condensation at hair follicles is locally directed by an epidermal prepattern. However, imposing this prepattern's condition of high FGF and low BMP activity across the entire skin reveals a latent dermal capacity to undergo spatially patterned self-organisation in the absence of epithelial direction. This mesenchymal self-organisation relies on restricted transforming growth factor (TGF) β signalling, which serves to drive chemotactic mesenchymal patterning when reaction-diffusion patterning is suppressed, but, in normal conditions, facilitates cell movement to locally prepatterned sources of FGF. This work illustrates a hierarchy of periodic patterning modes operating in organogenesis.
- MeSH
- buněčná diferenciace MeSH
- inbrední kmeny myší MeSH
- kůže cytologie embryologie metabolismus MeSH
- myši MeSH
- rozvržení tělního plánu MeSH
- signální transdukce MeSH
- stanovení celkové genové exprese MeSH
- transformující růstový faktor beta metabolismus fyziologie MeSH
- vlasový folikul embryologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Hair follicles are unique organs undergoing regular cycles of proliferation, differentiation, and apoptosis. The final step of apoptosis is, in general, mediated by executioner caspases comprising caspase-3, -6 and -7. Despite their commonly accepted apoptotic function, executioner caspases also participate in non-apoptotic processes. In the present study, we investigated activation (cleavage) of caspase-7 in mouse hair follicles and surrounding tissue during embryonic development into adulthood. Casp7 (-/-) mice were examined to understand the effect of caspase-7 deficiency in the skin. The activated form of caspase-7 was observed during embryonic hair follicle development, as well as in the first hair cycle. In general, activation of caspase-7 did not correlate with apoptosis and activation of caspase-3, except during physiological hair follicle regression. Notably, cleaved caspase-7 was observed in mast cells and its deficiency in the adult skin resulted in increased mast cell number. Our study shows for the first time activated caspase-7 in hair follicles and mast cells and indicates its non-apoptotic roles in the skin.
- MeSH
- aktivace enzymů MeSH
- apoptóza * MeSH
- exprese genu MeSH
- kaspasa 3 metabolismus MeSH
- kaspasa 7 nedostatek genetika metabolismus MeSH
- kaspasy genetika metabolismus MeSH
- kůže embryologie metabolismus MeSH
- mastocyty metabolismus MeSH
- myši knockoutované MeSH
- myši MeSH
- počet buněk MeSH
- transport proteinů MeSH
- vlasový folikul embryologie metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The Myb transcription factors are involved in essential cellular processes, such as cell proliferation, differentiation and cell death. Biological functions carried out by specific Myb proteins are distinct. Hair follicles are ectodermal-derived organs with cycling character of the growth resulting from the presence of somatic stem cells. In this study, we followed the expression of the Myb proteins in developing hair follicles and in the hair follicle stem cell niche by immunofluorescence staining. During hair follicle development, B-Myb was present in a few cells located in the area of cell division; c-Myb was abundant postanally in dividing cells but also in keratinizing zone. In addition, c-Myb was also detected in cells under the hair follicle bulge. These findings indicate possible involvement of c-Myb in regulation of activated stem cells leaving the niche.
Základy vlasových folikulů se vytvářejí již v embryonálním období a pro jejich vývoj je nezbytná přesná interakce mezi epidermis a dermis. Vlas je součástí pilosebaceózní jednotky. Skládá se z epiteliálních a dermálních komponent. Významnou součástí folikulu je dermální papila a oblast výskytu multipotentních kmenových buněk v zevní epiteliální pochvě (u myšího folikulu označovaná jako „bulge“ – výduť). Struktura folikulu se mění v závislosti na vlasovém cyklu, v němž se opakuje období aktivního růstu (anagen), krátká přechodná fáze (katagen) a období klidu (telogen). Za normálních okolností je výměna vlasů u člověka asynchronní. Regulace růstu vlasů je velice složitá a kromě růstových faktorů, adhezních molekul, cytokinů a jiných látek se zde významně uplatňují hormony, zejména androgeny, které hrají důležitou roli u nejčastějšího typu řídnutí vlasů, tzv. androgenetické alopecie. Ztráta vlasů jakékoliv etiologie může být zdrojem závažných psychických problémů.
The fundamentals of hair follicles are formed as early as the embryonic period and a precise interaction between the epidermis and the dermis is essential for their development. The hair is a part of the pilosebaceous unit. It is composed of epithelial and dermal components. An important part of the follicle is the dermal papilla and an area of occurrence of multipotent stem cells in the external epithelial sheath (referred to as "bulge" in the murine follicle). The structure of a follicle varies depending on the hair cycle that consists of an active growth phase (anagen), a short transition phase (catagen), and a rest phase (telogen). Under normal circumstances, the hair cycle is asynchronous in humans. Hair growth regulation is very complex and, in addition to growth factors, adhesion molecules, cytokines, and other substances, hormones are significantly involved here, particularly androgens that play a major role in the most common type of hair thinning, i. e. androgenetic alopecia. Hair loss of any etiology can be a source of serious mental problems.
- Klíčová slova
- pilosebaceózní jednotka, anagen, katagen, telogen, vypadávání vlasů,
- MeSH
- alopecie etiologie MeSH
- lidé MeSH
- nemoci vlasů etiologie MeSH
- vlasový folikul * anatomie a histologie embryologie fyziologie MeSH
- vlasy, chlupy * anatomie a histologie fyziologie růst a vývoj MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Understanding the mechanisms governing and regulating self-organisation in the developing embryo is a key challenge that has puzzled and fascinated scientists for decades. Since its conception in 1952 the Turing model has been a paradigm for pattern formation, motivating numerous theoretical and experimental studies, though its verification at the molecular level in biological systems has remained elusive. In this work, we consider the influence of receptor-mediated dynamics within the framework of Turing models, showing how non-diffusing species impact the conditions for the emergence of self-organisation. We illustrate our results within the framework of hair follicle pre-patterning, showing how receptor interaction structures can be constrained by the requirement for patterning, without the need for detailed knowledge of the network dynamics. Finally, in the light of our results, we discuss the ability of such systems to pattern outside the classical limits of the Turing model, and the inherent dangers involved in model reduction.
- MeSH
- biologické modely MeSH
- mezibuněčná komunikace fyziologie MeSH
- morfogeneze fyziologie MeSH
- myši MeSH
- vlasový folikul embryologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- alopecie etiologie chirurgie MeSH
- dospělí MeSH
- lidé MeSH
- ret chirurgie MeSH
- rozštěp rtu chirurgie komplikace MeSH
- vlasový folikul embryologie transplantace MeSH
- vlasy, chlupy embryologie transplantace MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
