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Origin and regenerative potential of vertebrate mechanoreceptor-associated stem cells
No full textWidera D, Hauser S, Kaltschmidt C, Kaltschmidt B. Origin and regenerative potential of vertebrate mechanoreceptor-associated stem cells. Anatomy Research International. 2012;2012:1-9.Meissner corpuscles and Merkel cell neurite complexes are highly specialized mechanoreceptors present in the hairy and glabrous skin, as well as in different types of mucosa. Several reports suggest that after injury, such as after nerve crush, freeze injury, or dissection of the nerve, they are able to regenerate, particularly including reinnervation and repopulation of the mechanoreceptors by Schwann cells. However, little is known about mammalian cells responsible for these regenerative processes. Here we review cellular origin of this plasticity in the light of newly described adult neural crest-derived stem cell populations. We also discuss further potential multipotent stem cell populations with the ability to regenerate disrupted innervation and to functionally recover the mechanoreceptors. These capabilities are discussed as in context to cellularly reprogrammed Schwann cells and tissue resident adult mesenchymal stem cells
Expression of developmentally regulated transcription factors in Merkel cell carcinoma
No full textWe have examined a number of developmentally regulated transcription factors for expression in Merkel cells and MCC cell lines and demonstrated that their expression patterns may be prognostic in MCC. We have shown that human Merkel cells from adult scalp hair follicle and from neonatal foreskin epidermal sheets express Brn-3c and HATH1. In addition, results demonstrate that the novel Merkel binding activity complex MNF contains Brn-3c. Moreover, Classic lines which retain neuroendocrine phenotype, are slow growing in culture, grow in suspension and are thought to be less aggressive, retain Brn-2, Brn-3c and HATH1 expression, whereas Variant suspension lines which no longer express NE markers retain Brn-2 and Brn-3c expression, but lack HATH1. Further, Type IV Variant lines which grow as adherent monolayers have shorter doubling times, are more radiation- resistant and have higher cloning efficiencies in soft agar, all thought to be indicative of aggressive tumours, have reduced or no Brn-2 proteins and lack expression of Brn-3c and HATH1 transcription factors.No Full Tex
Immunohistochemical characterization of normal canine Merkel cells
No full textCutaneous Merkel cells (MCs) have been well documented in humans, but less in other mammals. In dogs, there are only a few references about immunohistochemical characterization of MCs. We present the immunohistochemical profile of MCs in the dog for the most reliable antibodies used in human medicine. Tissue samples from several locations were obtained from five adult dogs of both sexes and different age and breed, fixed in 10% buffered formalin, embedded in paraffin wax and cut in 3-mum tissue sections. The ABC method was used with different poly- and monoclonal antibodies. Positive immunoreaction was found in MCs of hair follicles, skin and mucosae of several locations in each dog studied for anticytokeratins 8, 18 and 20, anti-neurofilaments, anti-chromogranin A, anti-neuron-specific enolase, and anti-synaptophysin. Immunoreaction was always cytoplasmic with differences in intensity, pattern of intracytoplasmic distribution and reaction type. Other cytokeratins, anti-S100 protein, anti-vimentin and anti-glial fibrillary acid protein were absent in canine normal MCs.5549
Expression of developmentally regulated transcription factors in merkel cell carcinoma
No full textWe have examined a number of developmentally regulated transcription factors for expression in Merkel cells and MCC cell lines and demonstrated that their expression patterns may be prognostic in MCC. We have shown that human Merkel cells from adult scalp hair follicle and from neonatal foreskin epidermal sheets express Brn-3c and HATH1. In addition, results demonstrate that the novel Merkel binding activity complex MNF contains Brn-3c. Moreover, Classic lines which retain neuroendocrine phenotype, are slow growing in culture, grow in suspension and are thought to be less aggressive, retain Brn-2, Brn-3c and HATH1 expression, whereas Variant suspension lines which no longer express NE markers retain Brn-2 and Brn-3c expression, but lack HATH1. Further, Type IV Variant lines which grow as adherent monolayers have shorter doubling times, are more radiation- resistant and have higher cloning efficiencies in soft agar, all thought to be indicative of aggressive tumours, have reduced or no Brn-2 proteins and lack expression of Brn-3c and HATH1 transcription factors.No Full Tex
Merkel cells in grafted ESS are associated with neurons expressing neurofilament medium (NF-M).
No full textImmunochemistry with antibodies against NF-M (red) and KRT20 (green) was used to localize neurons and Merkel cells, respectively, in ESS after grafting to mice. Nuclei were counterstained with DAPI (blue; B, C, E, F, H, I, K, L). Shown are cross sections of ESS at 4 weeks (A-C), 6 weeks (D-F), 8 weeks (G-I), and 12 weeks (J-L) after grafting; each row contains images of the same section. Images shown in the right-hand column (C, F, I, L) are 3-fold magnified images of boxed areas in center column (B, E, H, K). Scale bars in panels in first row are same for all images in column. White arrows indicate examples of NF-M-positive nerves associated with or in proximity to Merkel cells; yellow arrows indicate NF-M-positive nerves not associated with Merkel cells.</p
Molecular expression associated with vibrissa follicle development and differentiation
No full textThe hair follicle is a complex mini-organ formed as a result of epithelial mesenchymal interactions, provided by three different stem cell sources: epithelial, neural crest and mesenchymal. Hair follicle morphogenesis is directed by a distinct set of molecular signals which are unique to each stage of development. These interactions continue into the adult cycle, represented by periods of rapid growth (anagen), apoptosis driven regression (catagen), a period of relative quiescence (telogen) and shedding of the club hair (exogen). Many of the molecules involved have been elucidated such as Wnts, Bmps, Fgfs, TGF-ßs and Shh amongst others. However, the nature of their regulation and effect on gene expression is still unclear. Id proteins are emerging as powerful players in the transcriptional control of many fundamental biological processes, such as the cell cycle, proliferation and differentiation, apoptosis and lineage commitment. As a result, the expression patterns of Id2 and Ids were investigated by immunocytochemistry in developing and adult vibrissae. Wistar rats aged E14toP4 were used to cover all stages of vibrissae development (stages 0-6+) and 3-6 month old rats for the adult stages. This thesis reports that high Id2 expression was seen in specialised neuroendocrine cells (Merkel cells) of the hair follicle and basal epidermis, confirmed by co-expression of the Merkel cell marker, cytokeratin-20. This post-mitotic Id2 expression continued through postnatal ages and into the adult follicle. Staining with Id3 was characterised by cytoplasmic, basally polarised expression in the epithelia of stage 1-4 follicles. After this stage, expression switched to being nuclear with high levels in many different cell types including the dermal papilla, dermal sheath and outer root sheath, ш and Id3 expression was also investigated in retinole acid induced differentiation of E13.5 and E14 mystacial pads, studying the glandular morphogenesis of vibrissae and the effect on Id protein expression. Ш and Id3 immunoreactivity was cytoplasmic and polarised but no evidence of nuclear staining was seen.Id2 and ИЗ expression in developing vibrissae is reported here for the first time, describing the profiles of these proteins during hair follicle development and differentiation. These findings highlight an important cytoplasmic role for Id proteins in development and may have implications for reciprocal epithelial- mesenchymal interactions, pattern formation and stem cells in the hair follicle
Unterthänigste Anrede an die Durchlauchtigste Landes-Herrschaft, bey Höchstderoselben Anwesenheit zu Torgau, am 14. Octobr. 1773.
No full textgehalten von M. Gottlieb Merkel, Pfarrer und SuperintendentenVorlageform des Erscheinungsvermerks: Torgau, gedruckt bey F. S. Rüdel
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