Browsing by Subject "Hair follicle"

Now showing 1 - 4 of 4
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    Expression of transforming growth factor í3 isoforms and their receptors during hair growth phases in mice
    (Murcia : F. Hernández, 1996) Wollina, Uwe; Lange, D.; Funa, K.; Paus, R.
    Transforming growth factor B (TGF-6) is a family of potent growth inhibitor proteins, often produced as a precursor and often secreted in a complex with the latent TGF-B binding protein (LTBP). We investigated the expression of TGF-B1, 42, 43, LTBP, TGF-B receptor proteins type 1 and type 11 (TBR-1 and -11) during induced hair growth in C57 BL-6 mice. We here demonstrated that TGFBs and TBR-1 are expressed in hair follicle epithelium and have found a positive reactivity for LTBP and TBR-1 in sebocytes. Dermal tissue was weakly stained for LTBP and TGF-B3. In early anagen the inner hair root sheath epithelium expressed TGF-B1, whereas outer hair root was positive for TBR-1 during anagenlcatagen switch. TER-11 was found in sebaceous glands without significant variations during the hair cycle. We may conclude that in follicle epithelium TGF-Bl is not produced in a complex together with LTBP. On the other hand, it is possible that other types of LTBP, like LTBP-2 and LTBP-3, are present, which are not detected by the antibody we used. Furthermore, a very rapid secretion of LTBP fromproducing cells may prevent immunohistochemical detection. TGF-Bl released by inner hair root sheath may regulate outer root sheath growth. A bidirectional interaction of sebocytes and hair follicle epithelium in the TGF-BILTBP seems possible. Sebocytes can be considered to be a target for TGFs since they express both TBR-1 and -U. The general properties of TGF-B as a growth inhibitor of epithelial cells may suggest a possible involvement in either the abrogation of extensive growth at the end of anagen or the initiation of catagen for the follicle epithelium as well as growth control for sebaceous glands.
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    Immunoexpression of adhesion molecules during human fetal hair development
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Andrade Silva, Laura Maria; Hsieh, Ricardo; Lourenço, Silvia Vanessa; Ottoni, Verônica; Valente, Neusa; Dumet Fernandes, Juliana
    Introduction. Hair follicles are produced in a cyclical manner and the machinery involved in the reproduction of these follicles is present since the fetal stage. Although extensive research has been done on the human hair follicle, very little is known about the importance of adhesion molecules in its development. Material and methods. We analyzed here, the immunoexpression of beta-1 integrin, p-cadherin, e- cadherin, and beta-catenin in hair follicles from 26 formalin-fixed and paraffin-embedded skin samples from human embryos and fetus between 12-23 weeks of gestational age. Results. The adhesion molecules beta-1 integrin and e-cadherin/p-cadherin were expressed from 12 weeks and seemed to play a role in regulating epidermis invagination. Beta-catenin immunostaining was negative in all cases; down regulation of this protein may be necessary for fetal hair development and thus facilitating hair follicle down growth. Discussion/Conclusion. Adhesion molecules are essential for hair follicle down growth and proliferation; integrins and cadherins play a major role in this process. More studies are needed to describe hair follicle development
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    Immunohistochemical evaluation of intermediate filament nestin in dog hair follicles
    (Murcia : F. Hernández, 2008) Mercati, F.; Pascucci, L.; Gargiulo, A.M.; Dall’Aglio, C.; Ceccarelli, P.
    Hair follicles (HFs) are self-renewing structures that reconstitute themselves through the hair cycle. They maintain reservoirs of stem cells (SC) that are thought to reside in the bulge area, a region localized in the lowermost permanent portion of HFs. In mice and humans, HF bulge cells express nestin and present stem features as pluripotency. Nestin is a class VI intermediate filament protein; it was first described as a specific marker of CNS stem cells, but recent studies suggest that it may represent a more general stem cell marker (Wiese et al., 2004; Hoffman, 2006). Bulge cell characteristics have mainly been studied in mice and humans, but recently, a bulge-like region was identified also in dog HFs (Pascucci et al., 2006). In this work we investigate the presence and localization of nestin in dog HFs with the aim of evaluating its expression and to correlate it with the location of the bulge-like region. Immunostaining of skin samples collected from healthy dogs was performed by using a rabbit anti-nestin polyclonal antibody. The presence of a population of immunoreactive cells was revealed in the hair follicle middle region, at the arrector pili muscle insertion level. An immunohistochemical signal was detected only in primary hair follicles throughout the hair cycle. These observations led us to conclude that nestin positive cells are located in the bulge-like region of dog HFs and strengthen our hypothesis regarding the correlation between this region and the dog HF stem compartment.
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    Sequential expression of glutathione-S-transferase
    (Murcia : F. Hernández, 1995) Wollina, Uwe; Paus, R.; Feldrappe, S.
    The hair follicle is a stnicture showing a very unique cycling of its epithelial components. It is innervated by an abundance of peptidergic nerves, and neuroendocrine cells occur within the epithelium or in close proximity to it. Recently, it has been suggested that hair growth may be regulated by neuropeptides. We therefore investigated the relationship of VIP receptor expression to intracellular phosphotyrosinase and caldesmon involved in the control of growth and differentiation and metabolizing isoenzymes of the glutathione-S-transferase (GST) family alpha, mu, and pi during induced anagen of C57 BI-6 mice by immunohistotochemistry. It was demonstrated that GST isoenzymes were expressed sequentially in the bulge area and the inner hair root sheath as well as in the sebaceous gland epithelium. Caldesmon was present during the early anagen phases within the bulge region, as was phosphotyrosinase. However, phosphotyrosinase expression decreased in late anagen, and recovered again in post-epilation telogen. VIP receptor was expressed within the bulge area during anagen V, but was absent during the other cycle phases. These results suggest a relationship of protein expression to hair cycle phases and in particular a physiological function of VIPIVIP receptor in terminating the extensive hair follicle growth during anagen 1 to IV.