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| ABSTRACT |
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| Year : 2011 | Volume
: 3
| Issue : 3 | Page : 12-13 |
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Session E: Innovations in Hair Research
| Date of Web Publication | 16-Jun-2011 |
Correspondence Address:
 Source of Support: None, Conflict of Interest: None  | Check |
How to cite this article:
. Session E: Innovations in Hair Research. Int J Trichol 2011;3, Suppl S1:12-3 |
Utilizing RNAi and nanotechnology to study bulge stem cells
Dan Peer
Laboratory of Nanomedicine, Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences and Center for Nanosicence and Nanotechnology, Tel Aviv University, Tel Aviv, Israel.
E-mail: [email protected]
The hair follicle (HF) corresponds to a miniature organ, which during the normal lifespan of a human regenerates itself more than 10 times. Existing follicles undergo cycles of growth (anagen), regression (catagen) and rest (telogen) where the responsible cells for this remarkable process are the HF SCs (HFSCs) which reside in the bulge region. The hair cycle represents a remarkable model for study the regulation of SC quiescence and activation in the context of SC niche cross-talk. In recent years, the advances in SCs isolation methods enable the existence of SCs transcription profile, revealing a list of genes express highly in HFSCs. In-vivo manipulations of gene expression levels in SCs at their niche may clarify gene function and uncover the major players that are involved in regulation of SCs fate. However, elucidating gene function using classical genetic methods, such as transgenic mice, consume major resources and time for each candidate gene examined. In addition, gene knockout harbor a complete ablation that harden results interpretations by promoting compensation mechanisms. Our lab specialized in the development and characterization of targeted nanovectors with the ability to deliver therapeutic payloads including RNAi. Here, we present some of our efforts to develop topical RNAi delivery platforms to target specifically the HFSCs and to exploit these strategies as new approach to study SC biology in general and more specifically to study how to manipulate HFSCs fate.
Characterization of de novo generated fiber-producing human hair follicle equivalents in vitro
Gerd Lindner, Reyk Horland*, IlkaWagner, Beren Atac, Roland Lauster
Department of Biotechnology, Technische Universität Berlin, Berlin, Germany.
*E-mail: [email protected]
Here we describe the bioengineering of human hair follicle equivalents in vitro. These microfollicles display key characteristics of human vellus-like hair follicles. Mesenchymal, ektodermal and neuro-ektodermal originated primary cells from dissected human hair follicles were isolated and expanded. Dermal papilla fibroblasts have been kept under low adherent culture conditions resulting in the formation of dermal papilla-like aggregates. These spheroids underwent extra cellular matrix protein coating. In subsequent co-culture procedures keratinocyte and melanocyte attachment to the dermal papilla spheroids was forced to allow further follicular development. Raster electron microscopy and immunofluorescence staining of cryo-sectioned microfollicles were performed to reveal spatiotemporal development and to characterize hair follicle like structures. The self-organizing micro-organoids generate separated segments enclosed by extracellular matrix membranes, sheath formations and the production of a hair shaft-like fiber. Central ECM proteins and defined mesenchymal and epithelial markers were expressed. Selected Cytokeratin 15 and Ki67-positive but also apoptotic keratinocytes were detected in the outer microorganoid layer whereas single dermal papilla fibroblasts were seen TUNEL positive in the innermost aggregate. Inner root sheath formation was revealed by trichohyalin immunoreactivity and the melanocytic marker p-Mel17, c-kit and TRP-1 were expressed in the supra-papillary region of the microfollicle. We show that the de novo formation of human microfollicles in vitro is accompanied with basic hair follicle like characteristics. With further improvements, the generated microfollicles might in future be used as implants for treating reduced hair conditions. In vitro testing of hair-modulating effects of substances might be performed with single microfollicles or embedded in an engineered full thickness skin equivalent.
The bulge area is the major hair follicle source of nestin-expressing pluripotent stem cells
Fang Liu 1,2,3 , Aisada Uchugonova 1,4 , Hiroaki Kimura 1,2,5 , Chuansen Zhang 3 , Ming Zhao 1 , Lei Zhang 1,2 , Karsten Koenig 4 , Jennifer Duong 1 , Ryoichi Aki 1,6 , Norimitsu Saito 1,6 , Sumiyuki Mii 1,6 , Yasuyuki Amoh 6 , Kensei Katsuoka 6 , Robert M. Hoffman 1,2 *
1 AntiCancer Inc., San Diego, California, USA; 2 Department of Surgery, University of California San Diego, San Diego, California, USA; 3 Department of Anatomy, Second Military Medical University, Shanghai, China; 4 Department of Biophotonics and Laser Technology, Saarland University, Saarbruecken, Germany; 5 Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan; 6 Kitasato University, School of Medicine, Kanagawa, Japan.
*E-mail: [email protected]
Nestin has been shown to be expressed in the hair follicle, both in the bulge area (BA) as well as the dermal papilla (DP). Nestin-expressing stem cells of both the BA and DP have been previously shown to be pluripotent and be able to form neurons and other non-follicle cell types. The nestin-expressing pluripotent stem cells from the DP have been termed skin precursor or SKP cells. The objective of the present study was to determine the major source of nestin-expressing pluripotent stem cells in the hair follicle and to compare the ability of the nestin-expressing pluripotent stem cells from the BA and DP to repair spinal cord injury. Transgenic mice in which the nestin promoter drives GFP (ND-GFP) were used in order to observe nestin expression in the BA and DP. Nestin-expressing DP cells were found in early and middle anagen. The BA had nestin expression throughout the hair cycle and to a greater extent than the DP. The cells from both regions had very long processes extending from them as shown by two photon confocal microscopy. Nestin-expressing stem cells from both areas differentiated into neuronal cells at high frequency in vitro. Both nestin-expressing DP and BA cells differentiated into neuronal and glial cells after transplantation to the injured spinal cord and enhanced injury repair and locomotor recovery within four weeks. Nestin-expressing pluripotent stem cells from both the BA and DP have potential for spinal cord regeneration, with the BA being the greater and more constant source.
Sphere formation restores hair-inductive activity of cultured human dermal papilla cells
Young Kwan Sung*, Bo Mee Kang, Moon Kyu Kim, Jung Chul Kim
Department of Immunology, School of Medicine, Kyungpook National University, Daegu, Korea.
*E-mail: [email protected]
Two dimensional (2D) cultured DP cells are known to gradually lose hair-inductive capacity during subculture. Recent studies showed that sphere formation enhances hair-inductive activity of cultured murine vibrissal DP cells. These results suggest that hair-inducing capacity of human DP cells can also be restored by three dimensional (3D) spheroid cultures and provoked us to evaluate the hair-inducing capacity of cultured human DP spheres. Hair-inductive capacity of cultured human DP spheres was assessed using patch assay, one of the hair regeneration methods. We observed hair follicle formation when human DP spheres from various passages of culture are mixed with newborn epidermal cells of C57BL/6 mouse. In contrast, hair follicles were never observed when 2D cultures from the same population are employed. DiI labeling of DP cells clearly showed that hair follicles are not the result of mouse dermal contamination but are induced by human DP cells. In conclusion, we, first time to our knowledge, show that sphere formation restores hair-inductive activity of human DP cells.
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