Where are the nestin-labelled stem cells in the hair follicle - Essay Example

?Where are The Nestin-Labelled Stem Cells In The Hair Follicle? Introduction Stem Cells Stem cells are defined as cell with the ability to generate differentiated cells and the capacity to self renew. The reason why they are called stem cells is because of their ability to generate different cells. Many cells stem from them. The cells have the ability to renew themselves, generate daughter cells identical to their mothers and to create progeny that can differentiate to other cells (Kelly, 2007, p. 4). They are classified according to their origin. Those from the embryo for example are called embryonic stem cells; there are also adult stem cells and embryonic germ stem cells (Kelly, 2007, p. 4 and Bongso & Lee, 2010, p. 2). Stem cells have three very important characteristics that differentiate them from other cells. These are; They are unspecialized cells They can be induced with special functions to become specialized cells and They have the ability to differentiate to specialized cells (Kelly, 2007, p. 5 and Grace & National Academies Press, 2006). Because of these characteristics, stem cells are very important in reparative or regenerative medicine. Having the ability to produce specialized cells means they can be used to form specialized cells to replace the damaged ones; and being unspecialized also means they can be induced to form specialized cells for tissue repair or replacements (Kelly, 2007, p. 5 and Grace & National Academies Press, 2006). Stem cell research is one of the most promising areas in basic research. Initial research involved the use of their regenerative ability to repair organs due to injury, but now there is increasing interest in what these cells can do in the pathogenesis of disease processes (Fong, 2007, p. 6). Knowledge and understanding of attributes and control of stem cells, enables scientists to understand human development and disease pathogenesis. Diseases like cancers are thought to be as a result of abnormal cell differentiation and proliferation. An understanding of cell proliferation in stem cells can help in finding out the causes of such cancers, preventive measures and their treatments (Murnaghan, 2010). It has been used in understanding birth defects and in cell therapies. Currently, stem cell research has reached a level where it is used to treat some cancers for example leukemia and other diseases where bone marrow transplants solve the problem. Other areas it is likely to help are; stroke, type I diabetes, Parkinson’s disease, spinal cord injuries, Alzheimer’s diseases and Retinal diseases (Murnaghan, 2010). A lot more is still going on and scientists are exploiting information available on stem cell research that can help treat or provide a solution to most of human diseases (Hoffman, 2007 and Steindler, 2007, p. 323). In this case, stem cells in the hair follicle have been found to be important and the aim of the research is to find where such stem cells are in the follicle. The reason for targeting nestin-labelled stem cells in the hair follicle is because of the relative accessibility of the tissue and the identified role of these stem cells in restoring nerve function and nerve regeneration (Hoffman, 2007 and Shastri, 2010, p. 63). Nestin-labelled Stem Cells The hair follicle has been found to be an easily accessible source of pluripotent adult stem cells (Shakhova & Sommer, 2010, Hoffman, 2007). Nestin is a protein marker for neural stem cells; these markers are also expressed in the stem cells of hair follicle and the differentiated progeny of the follicle (Amoh et al, 2005 (a) and Hoffman, 2007). Because of this expression, nestin-labelled stem cells in the hair follicle could be an easily accessible source of such neural stem cells. Amoh, Li, Katsuoka and Hoffman (2005), found that stem cells from the hair follicle are pluripotent, primitive and have the capability of differentiating into diverse and multiple types of cells. These characteristics have been confirmed by several scientists and scientific research studies (Hoffman, 2007, Amoh et al, 2004; Amoh et al, 2005 (c); Amoh, 2009; Cotsarelis, 2006; S14 and Kelly, 2007). The pluripotent nestin-labelled stem cells (invitro) differentiate into keratinocytes, neurons, smooth muscle cells, glia and melanocytes. While in vivo, according to Hoffman, (2007) after transplantation in subcutis of nude mice, they can differentiate into neural tissue and blood vessels after transplantation. Hair follicle stem cells have been found to improve the restoration of the nerve function and increase the rate of regeneration of the nerves (Hoffman, 2007, Amoh, 2009, p. 3 and Amoh et al, 2005 (c). Amoh (2009) noted that an implantation of GFP hair follicle stem cells into a severed sciatic nerve gap region restored the nerve function and increased the rate of nerve regeneration. The cells then differentiated to Schwann cells after transplantation to the disengaged nerves (Amoh, 2009, p. 3). Amoh and others (2005 (b)), have the same results of hair follicle stem cells differentiating into Schwann cells and helping in regeneration of peripheral nerves that have been detached. Amoh and others (2004) also indicate that the stem cells differentiate and proliferate to the above named invitro products inclusive of adipocytes. Importance of Nestin-labeled stem cells in Regenerative Medicine As noted earlier, Nestin labeled stem cells are neural stem cells and based on the characteristics of stem cells, these stem cells can help in therapies of nerve related problems and understanding of studies related to the neural system. More studies have confirmed the role of these nestin-labbelled stem cells found in the hair follicle in nerve regeneration and functional restoration. Because of the hair follicle is an easily accessible source of neural stem cells that can be used in research, it is important to find out the location of the stem cells in the hair follicles. Problem: One major problem however, is where these stem cells are located. Amoh and others (2004) noted that the exact location as well as the functions of stem cells that proliferate and differentiate into glia, smooth muscle cells, adipocytes and neurons was unknown. One of the reasons for lack of such information is the lack of extensive research on epidermal stem cell research compared to other lineages of stem cell. According to (S14), epidermal stem cell research experiences a lot of difficulties such as; technical difficulties with culturing epidermal cells invitro, lack of biological assays to demonstrate stem cell like characteristics and lack of identification and isolation of these markers (Leor, 2007, p. 397). What is currently known is that the stem cells’ principle location is the follicular bulge region (Amoh et al, 2004). This is because studies have shown that bulge cells have stem cell characteristics such as the cardinal feature of serenity, the potential to proliferate highly and multipotency. Analysis of the lineage show that adult follicle and hair epithelial layers originate from the bulge cells. The function of these cells is to when isolated, the regenerate the sebaceous gland, the new hair follicle and the epidermis when combined with neonatal dermal cells. These are characteristics of stem cells and because of such results; scientists believe that the stem cells are located in the bulge region (Cotsarelis, 2006). Aim: It is important to find out the specific location of these cells and for that reason, this research is focused on establishing the exact location of nestin-labelled stem cells in the hair follicle. Methodology: There have been several methods used in identification of stem cells’ locations. These are such as histochemical and immunohistochemical techniques (Fellous et al, 2009, p. 1655), triple immunogold labeling for determination of hemopoietic stem cell location (Ellis et al, 2009), stem cell labeling (Landgren & Curtis, 2010, p. 1) and label retaining cell assays such as BrdU (Li, Lu, & Lu, 2010). In this research, immunohistochemistry will be used to determine the presence of nestin expressing cells in the hair follicles. As indicated above, immunohistochemical techniques have been used to identify the location of stem cells. The method will involve differentiation of different sections of the hair follicle structure. Frozen sections of hair follicles will be prepared using Cryostat and stained with advanced histological stain which will show the different sections of the structure in different colours. These differentiations will help determine the specific location of nestin labeled stem cells in the hair follicle. Wasta indicates that in order to identify the location of stem cells, researchers have to know the exclusive receptor in the stem cell that differentiates it from millions of other cells (n.d). In this case, this exclusive feature is nestin which is expressed in the stem cells of interest. Identification of these cells in stained hair follicle will involve immunohistochemistry using keratin 6, an antibody to nestin. The presence of nestin labeled stem cells in the hair follicle will be shown by the antibody reaction which will also help in determining the location of such cells. References Amoh, Y., 2009, Multipotent Nestin-Expressing Hair Follicle Stem Cells, Journal of Dermatology, 36: pp. 1–9. Amoh, Y., Li, L., Katsuoka, K. and Hoffman, R. M., 2005, Identification of A Multipotent Nestin-Positive, Keratin-Negative Primitive Stem Cell in The Hair Follicle. Abstract. Retrieved on 6th December 2011 from: http://aacrmeetingabstracts.org/cgi/content/abstract/2005/1/480--S12 Amoh, Y., Li, L., Katsuoka, K., Penman, S. and Hoffman, R. M., (c) 2005, Multipotent Nestin Positive, Keratin-Negative Hair-Follicle Bulge Stem Cells Can Form Neurons, PNAS, 102 (15): pp. 5530–5534. Amoh, Y., Li, L., Yang, M., Jiang, P., Moossa, A. R., Katsuoka, K. and Hoffman, R. M., (a) 2005, Hair Follicle–Derived Blood Vessels Vascularize Tumors in Skin and Are Inhibited by Doxorubicin, Journal of Cancer Research, 65: pp. 2337-2343. Amoh, Y., Li, L., Campillo, R., Kawahara, K., Katsuoka, K., Penman, S. and Hoffman, R. M., (b) 2005, Implanted Hair Follicle Stem Cells Form Schwann Cells That Support Repair Of Severed Peripheral Nerves, PNAS, 102(49): pp. 17734-17738. Amoh, Y., Li, L., Yang, M., Moossa, A. R., Katsuoka, K., Penman, K. and Hoffman, R. M., 2004, Nascent Blood Vessels In The Skin Arise From Nestin-Expressing Hair-Follicle Cells, PNAS, 101 (36): pp. 13291-13295. Bongso, A. and Lee, E. H., 2010, Stem Cells: From Bench to Bedside, 2nd Ed., London: World Scientific. Cotsarelis, G. (2006). Epithelial Stem Cells: A Folliculocentric View, Journal of Investigative Dermatology, 126, pp. 1459–1468. Ellis, S. L., Williams, B., Asquith, S., Bertoncello, I. and Nilsson, S. K., 2009, An Innovative Triple Immunogold Labeling Method To Investigate The Hemopoietic Stem Cell Niche In Situ. Microsc Microanal, 15(5): pp. 403-14. Fellous, T. G., Islam, S., Tadrous, P. J., Elia, G., Kocher, H. M., Bhattacharya, S., Mears, L., Turnbull, D. M., Taylor, R. W., Greaves, L. C., Chinnery, P. F., Taylor, G., McDonald, S. A. C., Wright, N. A. and Alison, M. R., 2009, Locating the Stem Cell Niche and Tracing Hepatocyte Lineages in Human Liver, Hepatology, 49 (5): pp. 1655-1663. Fong, C. A., 2007, Stem Cell Research Developments, New York: Nova Publishers. Grace, E. S. and National Academies Press, 2006, Biotechnology Unzipped: Promises And Realities, 2nd Ed., Washington, DC: Joseph Henry Press. Hoffman, R. M., 2007, The Potential Of Nestin-Expressing Hair Follicle Stem Cells In Regenerative Medicine, Expert Opinion in Biological Therapy, 7(3): pp. 289-291. Kelly, E. B., 2007, Stem Cells, Westport, CT: Greenwood Publishing Group. Landgren, H., and Curtis, M. A., 2010, Locating and Labeling Neural Stem Cells in the Brain, Journal of Cellular Physiology, 226: 1–7. Leor, J., 2007, Stem Cell and Gene-Based Therapy: Frontiers in Regenerative Medicine, London: Springer. Li, F., Lu, L. and Lu, J., 2010, Identification and Location Of Label Retaining Cells In Mouse Liver, Journal of Gastroenterology, 45(1): pp. 113-121. Murnaghan, I., 2010, Why are Stem Cells Important? Retrieved on 6th December 2011 from: http://www.explorestemcells.co.uk/whyarestemcellsimportant.html. Shakhova, O. and Sommer, L., 2010, Neural Crest-Derived Stem Cells, In StemBook, ‘The Stem Cell Research Community’, StemBook. Retrieved on 6th December 2011 from: http://www.stembook.org/node/696. Shastri, V. P., 2010, Advances in Regenerative Medicine: Role of Nanotechnology, and Engineering Principles, Dordrecht, Netherlands: Springer. Steindler, D. A., 2007, Stem Cells, Regenerative Medicine, and Animal Models of Disease, ILAR Journal, 48 (4): pp: 323-338. Wasta, V., n.d., Stem Cell Research at John Hopkins: Stem Cell Signatures. Retrieved on 7th December 2011 from: http://www.hopkinsmedicine.org/stem_cell_research/keeping_track/stem_cell_signatures.html. Lui, F., Uchugonova, A., Kimura, H., Zhang, C., Zhao, M., Zhang, L., Koenig, K., Duong, J., Aki, R., Saito, N., Mii, S., Amoh, Y., Katsuoka, K., Hoffman, R. M., 2011, The Bulge Area Is The Major Hair Follicles Source Of Nestin-Expressing Pluripotent Stem Cells Which Can Repair The Spinal Cord Compared To The Dermal Papilla. 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